Methods and systems for boosting deep neural networks for deep learning

ABSTRACT

Methods and systems are disclosed for boosting deep neural networks for deep learning. In one example, in a deep neural network including a first shallow network and a second shallow network, a first training sample is processed by the first shallow network using equal weights. A loss for the first shallow network is determined based on the processed training sample using equal weights. Weights for the second shallow network are adjusted based on the determined loss for the first shallow network. A second training sample is processed by the second shallow network using the adjusted weights. In another example, in a deep neural network including a first weak network and a second weak network, a first subset of training samples is processed by the first weak network using initialized weights. A classification error for the first weak network on the first subset of training samples is determined. The second weak network is boosted using the determined classification error of the first weak network with adjusted weights. A second subset of training samples is processed by the second weak network using the adjusted weights.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is a U.S. National Phase application under 35U.S.C. § 371 of International Application No. PCT/CN2017/079774, filedApr. 7, 2017, entitled “METHODS AND SYSTEMS FOR BOOSTING DEEP NEURALNETWORKS FOR DEEP LEARNING”.

FIELD

Embodiments of the invention are in the field of data processingincluding image processing, graphics processing and machine learning.More particularly, embodiments of the invention relate to methods andsystems for boosting deep neural networks (DNNs) for deep learning.

BACKGROUND

Current parallel graphics data processing includes systems and methodsdeveloped to perform specific operations on graphics data such as, forexample, linear interpolation, tessellation, rasterization, texturemapping, depth testing, etc. Traditionally, graphics processors usedfixed function computational units to process graphics data; however,more recently, portions of graphics processors have been madeprogrammable, enabling such processors to support a wider variety ofoperations for processing vertex and fragment data.

To further increase performance, graphics processors typically implementprocessing techniques such as pipelining that attempt to process, inparallel, as much graphics data as possible throughout the differentparts of the graphics pipeline. Parallel graphics processors with singleinstruction, multiple thread (SIMT) architectures are designed tomaximize the amount of parallel processing in the graphics pipeline. Inan SIMT architecture, groups of parallel threads attempt to executeprogram instructions synchronously together as often as possible toincrease processing efficiency. A general overview of software andhardware for SIMT architectures can be found in Shane Cook, CUDAProgramming Chapter 3, pages 37-51 (2013).

Machine learning has been successful at solving many kinds of tasks. Thecomputations that arise when training and using machine learningalgorithms (e.g., neural networks) lend themselves naturally toefficient parallel implementations. Accordingly, parallel processorssuch as general-purpose graphic processing units (GPGPUs) have played asignificant role in the practical implementation of deep neuralnetworks. Parallel graphics processors with single instruction, multiplethread (SIMT) architectures are designed to maximize the amount ofparallel processing in the graphics pipeline. In an SIMT architecture,groups of parallel threads attempt to execute program instructionssynchronously together as often as possible to increase processingefficiency. The efficiency provided by parallel machine learningalgorithm implementations allows the use of high capacity networks andenables those networks to be trained on larger datasets.

One type of neural network is the Convolutional Neural Network (CNN),which can perform deep machine learning. The nodes in the CNN inputlayer are organized into a set of “filters,” which can act as featuredetectors. The output of each set of filters is propagated to nodes insuccessive layers of the network. CNN is thus useful in computer visionand image recognition applications because of its feature detectionabilities. Training or learning for a deep CNN, however, can becomputational intensive and a difficult and time expensive endeavor.Thus, what is needed are improved training techniques for deep CNNswhich are effective and efficient.

BRIEF DESCRIPTION N OF THE DRAWINGS

The appended drawings illustrate examples and are, therefore, exemplaryembodiments and not considered to be limiting in scope.

FIG. 1 is a block diagram illustrating a computer system configured toimplement one or more aspects of exemplary embodiments described herein.

FIG. 2A-2D illustrate a parallel processor components according to anexemplary embodiment.

FIGS. 3A-3B are block diagrams of graphics multiprocessors according toexemplary embodiments.

FIG. 4A-4F illustrate an exemplary architecture in which a plurality ofGraphic Processing Units (GPUs) are communicatively coupled to aplurality of multi-core processors.

FIG. 5 illustrates a graphics processing pipeline according to anexemplary embodiment.

FIG. 6 illustrates a machine learning software stack according to anexemplary embodiment.

FIG. 7 illustrates a highly-parallel general-purpose graphics processingunit according to an exemplary embodiment.

FIG. 8 illustrates a multi-GPU computing system according to anexemplary embodiment.

FIGS. 9A-9B illustrate layers of exemplary deep neural networks.

FIG. 10 illustrates an exemplary recurrent neural network.

FIG. 11 illustrates exemplary embodiment of training and deployment of adeep neural network.

FIG. 12 is an exemplary block diagram illustrating distributed learning.

FIG. 13 illustrates an exemplary inferencing system on a chip (SOC)suitable for performing inferencing using a trained model.

FIG. 14 is an exemplary block diagram of basic boosting architecturehaving a boosted deep neural network system (DNN) system to receivetraining data for learning and training a DNN.

FIG. 15A illustrates an exemplary process of boosting a deep CNNcomprised of shallow CNNs using the loss of each shallow CNN to trainthe deep CNN.

FIG. 15B is a flow diagram of an operation for boosting a deep CNNcomprised of shallow CNNs and to train the deep CNN using the loss ofeach shallow CNN according to an exemplary embodiment.

FIG. 16 illustrates an exemplary boosting process to train an ensembleof deep CNNs by combining weak CNN networks to form a strong CNNnetwork.

FIG. 17 is a block diagram of boosting architecture to train a deep CNNaccording to an exemplary embodiment.

FIGS. 18A-18B are flow diagrams of operations to boost a deep CNNcomprised of weak networks according to exemplary embodiments.

FIG. 19 illustrates a block diagram of a processing system according toan exemplary embodiment.

FIG. 20 illustrates an exemplary block diagram of an embodiment of aprocessor having one or more processor cores, an integrated memorycontroller, and an integrated graphics processor.

FIG. 21 illustrates an exemplary block diagram of a graphics processor.

FIG. 22 illustrates a block diagram of a graphics processing engine of agraphics processor according to exemplary embodiments.

FIG. 23 illustrates a block diagram of another exemplary embodiment of agraphics processor.

FIG. 24 illustrates thread execution logic including an array ofprocessing elements employed in exemplary embodiments of a graphicsprocessing engine (GPE).

FIG. 25 illustrates a block diagram of a graphics processor instructionformats according to exemplary embodiments.

FIG. 26 illustrates a block diagram of an exemplary embodiment of agraphics processor.

FIG. 27A illustrates a block diagram of a graphics processor commandformat according to an exemplary embodiment.

FIG. 27B illustrates a block diagram of a graphics processor commandsequence according to an exemplary embodiment.

FIG. 28 illustrates exemplary graphics software architecture for a dataprocessing system according exemplary embodiments.

FIG. 29 illustrates a block diagram of an IP core development systemthat may be used to manufacture an integrated circuit (IC) to performoperations according to an exemplary embodiment.

FIG. 30 illustrates a block diagram of an exemplary system on a chip ICthat may be fabricated using or one more IP cores according to anexemplary embodiment.

FIG. 31 illustrates a block diagram of an exemplary graphics processoron a system on a chip IC that may be fabricated using one or more IPcores according to an exemplary embodiment.

FIG. 32 illustrates a block diagram of an exemplary additional graphicsprocessor of a system on a chip IC that may be fabricated using one ormore IP cores according to an exemplary embodiment.

DETAILED DESCRIPTION

In some embodiments, a graphics processing unit (GPU) is communicativelycoupled to host/processor cores to accelerate graphics operations,machine-learning operations, pattern analysis operations, and variousgeneral purpose GPU (GPGPU) functions. The GPU may be communicativelycoupled to the host processor/cores over a bus or another interconnect(e.g., a high-speed interconnect such as PCIe or NVLink). In otherembodiments, the GPU may be integrated on the same package or chip asthe cores and communicatively coupled to the cores over an internalprocessor bus/interconnect (i.e., internal to the package or chip).Regardless of the manner in which the GPU is connected, the processorcores may allocate work to the GPU in the form of sequences ofcommands/instructions contained in a work descriptor. The GPU then usesdedicated circuitry/logic for efficiently processing thesecommands/instructions.

In some embodiments, an image capturing device is a standalone device tocapture an input image. The image capturing device, however, can be partof or a subcomponent of another computing device requiring imagecapturing capabilities such as a portable or hand-held computing devicewith a digital camera to capture images.

In the following description, numerous specific details are set forth toprovide a more thorough understanding. However, it will be apparent thatembodiments described herein may be practiced without one or more ofthese specific details. In other instances, well-known features have notbeen described to avoid obscuring the details of the exemplaryembodiments.

Computing System Overview

FIG. 1 is a block diagram illustrating a computing system 100 configuredto implement one or more aspects of exemplary embodiments describedherein. The computing system 100 includes a processing subsystem 101having one or more processor(s) 102 and a system memory 104communicating via an interconnection path that may include a memory hub105. The memory hub 105 may be a separate component within a chipsetcomponent or may be integrated within the one or more processor(s) 102.The memory hub 105 couples with an I/O subsystem 111 via a communicationlink 106. The I/O subsystem 111 includes an I/O hub 107 that can enablethe computing system 100 to receive input from one or more inputdevice(s) 108. Additionally, the I/O hub 107 can enable a displaycontroller, which may be included in the one or more processor(s) 102,to provide outputs to one or more display device(s) 110A. In oneembodiment, the one or more display device(s) 110A coupled with the I/Ohub 107 can include a local, internal, or embedded display device.

In one embodiment, the processing subsystem 101 includes one or moreparallel processor(s) 112 coupled to memory hub 105 via a bus or othercommunication link 113. The communication link 113 may be one of anynumber of standards based communication link technologies or protocols,such as, but not limited to PCI Express, or may be a vendor specificcommunications interface or communications fabric. In one embodiment,the one or more parallel processor(s) 112 form a computationally focusedparallel or vector processing system that an include a large number ofprocessing cores and/or processing clusters, such as a many integratedcore (MIC) processor. In one embodiment, the one or more parallelprocessor(s) 112 form a graphics processing subsystem that can outputpixels to one of the one or more display device(s) 110A coupled via theI/O Hub 107. The one or more parallel processor(s) 112 can also includea display controller and display interface (not shown) to enable adirect connection to one or more display device(s) 110B.

Within the I/O subsystem 111, a system storage unit 114 can connect tothe I/O hub 107 to provide a storage mechanism for the computing system100. An I/O switch 116 can be used to provide an interface mechanism toenable connections between the I/O hub 107 and other components, such asa network adapter 118 and/or wireless network adapter 119 that may beintegrated into the platform, and various other devices that can beadded via one or more add-in device(s) 120. The network adapter 118 canbe an Ethernet adapter or another wired network adapter. The wirelessnetwork adapter 119 can include one or more of a Wi-Fi, Bluetooth, nearfield communication (NFC), or other network device that includes one ormore wireless radios.

The computing system 100 can include other components not explicitlyshown, including USB or other port connections, optical storage drives,video capture devices, and the like, may also be connected to the I/Ohub 107. Communication paths interconnecting the various components inFIG. 1 may be implemented using any suitable protocols, such as PCI(Peripheral Component interconnect) based protocols (e.g., PCI-Express),or any other bus or point-to-point communication interfaces and/orprotocol(s), such as the NV-Link high-speed interconnect, orinterconnect protocols known in the art.

In one embodiment, the one or more parallel processor(s) 112 incorporatecircuitry optimized for graphics and video processing, including, forexample, video output circuitry, and constitutes a graphics processingunit (GPU). In another embodiment, the one or more parallel processor(s)112 incorporate circuitry optimized for general purpose processing,while preserving the underlying computational architecture, described ingreater detail herein. In yet another embodiment, components of thecomputing system 100 may be integrated with one or more other systemelements on a single integrated circuit. For example, the one or moreparallel processor(s), 112 memory hub 105, processor(s) 102, and I/O hub107 can be integrated into a system on chip (SoC) integrated circuit.Alternatively, the components of the computing system 100 can beintegrated into a single package to form a system in package (SIP)configuration. In one embodiment, at least a portion of the componentsof the computing system 100 can be integrated into a multi-chip module(MCM), which can be interconnected with other multi-chip modules into amodular computing system.

It will be appreciated that the computing system 100 shown herein isillustrative and that variations and modifications are possible. Theconnection topology, including the number and arrangement of bridges,the number of processor(s) 102, and the number of parallel processor(s)112, may be modified as desired. For instance, in some embodiments,system memory 104 is connected to the processor(s) 102 directly ratherthan through a bridge, while other devices communicate with systemmemory 104 via the memory hub 105 and the processor(s) 102. In otheralternative topologies, the parallel processor(s) 112 are connected tothe I/O hub 107 or directly to one of the one or more processor(s) 102,rather than to the memory hub 105. In other embodiments, the I/O hub 107and memory hub 105 may be integrated into a single chip. Someembodiments may include two or more sets of processor(s) 102 attachedvia multiple sockets, which can couple with two or more instances of theparallel processor(s) 112.

Some of the particular components shown herein are optional and may notbe included in all implementations of the computing system 100. Forexample, any number of add-in cards or peripherals may be supported, orsome components may be eliminated. Furthermore, some architectures mayuse different terminology for components similar to those illustrated inFIG. 1 . For example, the memory hub 105 may be referred to as aNorthbridge in some architectures, while the I/O hub 107 may be referredto as a Southbridge.

FIG. 2A illustrates a parallel processor 200 according to an exemplaryembodiment. The various components of the parallel processor 200 may beimplemented using one or more integrated circuit devices, such asprogrammable processors, application specific integrated circuits(ASICs), or field programmable gate arrays (FPGA). The illustratedparallel processor 200 is a variant of the one or more parallelprocessor(s) 112 shown in FIG. 1 according to an exemplary embodiment.

In one embodiment, the parallel processor 200 includes a parallelprocessing unit 202. The parallel processing unit includes an I/0 unit204 that enables communication with other devices, including otherinstances of the parallel processing unit 202. The I/O unit 204 may bedirectly connected to other devices. In one embodiment, the I/O unit 204connects with other devices via the use of a hub or switch interface,such as memory hub 105. The connections between the memory hub 105 andthe I/O unit 204 form a communication link 113. Within the parallelprocessing unit 202, the I/O unit 204 connects with a host interface 206and a memory crossbar 216, where the host interface 206 receivescommands directed to performing processing operations and the memorycrossbar 216 receives commands directed to performing memory operations.

When the host interface 206 receives a command buffer via the I/O unit204, the host interface 206 can direct work operations to perform thosecommands to a front end 208. In one embodiment, the front end 208couples with a scheduler 210, which is configured to distribute commandsor other work items to a processing cluster array 212. In oneembodiment, the scheduler 210 ensures that the processing cluster array212 is properly configured and in a valid state before tasks aredistributed to the processing clusters of the processing cluster array212 in one embodiment, the scheduler 210 is implemented via firmwarelogic executing on a microcontroller. The microcontroller implementedscheduler 210 is configurable to perform complex scheduling and workdistribution operations at coarse and fine granularity, enabling rapidpreemption and context switching of threads executing on the processingarray 212. In one embodiment, the host software can prove workloads forscheduling on the processing array 212 via one of multiple graphicsprocessing doorbells. The workloads can then be automaticallydistributed across the processing array 212 by the scheduler 210 logicwithin the scheduler microcontroller.

The processing cluster array 212 can include up to “N” processingclusters (e.g., cluster 214A, cluster 214B, through cluster 214N). Eachcluster 214A-214N of the processing cluster array 212 can execute alarge number of concurrent threads. The scheduler 210 can allocate workto the clusters 214A-214N of the processing cluster array 212 usingvarious scheduling and/or work distribution algorithms, which may varydepending on the workload arising for each type of program orcomputation. The scheduling can be handled dynamically by the scheduler210, or can be assisted in part by compiler logic during compilation ofprogram logic configured for execution by the processing cluster array212. In one embodiment, different clusters 214A-214N of the processingcluster array 212 can be allocated for processing different types ofprograms or for performing different types of computations.

The processing cluster array 212 can be configured to perform varioustypes of parallel processing operations. In one embodiment, theprocessing cluster array 212 is configured to perform general-purposeparallel compute operations. For example, the processing cluster array212 can include logic to execute processing tasks including filtering ofvideo and/or audio data, performing modeling operations, includingphysics operations, and performing data transformations.

In one embodiment, the processing cluster array 212 is configured toperform parallel graphics processing operations. In embodiments in whichthe parallel processor 200 is configured to perform graphics processingoperations, the processing cluster array 212 can include additionallogic to support the execution of such graphics processing operations,including, but not limited to texture sampling logic to perform textureoperations, as well as tessellation logic and other vertex processinglogic. Additionally, the processing cluster array 212 can be configuredto execute graphics processing related shader programs such as, but notlimited to vertex shaders, tessellation shaders, geometry shaders, andpixel shaders. The parallel processing unit 202 can transfer data fromsystem memory via the I/O unit 204 for processing. During processing thetransferred data can be stored to on-chip memory (e.g., parallelprocessor memory 222) during processing, then written back to systemmemory.

In one embodiment, when the parallel processing unit 202 is used toperform graphics processing, the scheduler 210 can be configured todivide the processing workload into approximately equal sized tasks, tobetter enable distribution of the graphics processing operations tomultiple clusters 214A-214N of the processing cluster array 212. In someembodiments, portions of the processing cluster array 212 can beconfigured to perform different types of processing. For example, afirst portion may be configured to perform vertex shading and topologygeneration, a second portion may be configured to perform tessellationand geometry shading, and a third portion may be configured to performpixel shading or other screen space operations, to produce a renderedimage for display. Intermediate data produced by one or more of theclusters 214A-214N may be stored in buffers to allow the intermediatedata to be transmitted between clusters 214A-214N for furtherprocessing.

During operation, the processing cluster array 212 can receiveprocessing tasks to be executed via the scheduler 210, which receivescommands defining processing tasks from front end 208. For graphicsprocessing operations, processing tasks can include indices of data tobe processed, e.g., surface (patch) data, primitive data, vertex data,and/or pixel data, as well as state parameters and commands defining howthe data is to be processed (e.g., what program is to be executed). Thescheduler 210 may be configured to fetch the indices corresponding tothe tasks or may receive the indices from the front end 208. The frontend 208 can be configured to ensure the processing cluster array 212 isconfigured to a valid state before the workload specified by incomingcommand buffers (e.g., batch-buffers, push buffers, etc.) is initiated.

Each of the one or more instances of the parallel processing unit 202can couple with parallel processor memory 222. The parallel processormemory 222 can be accessed via the memory crossbar 216, which canreceive memory requests from the processing cluster array 212 as well asthe I/O unit 204. The memory crossbar 216 can access the parallelprocessor memory 222 via a memory interface 218. The memory interface218 can include multiple partition units (e.g., partition unit 220A,partition unit 220B, through partition unit 220N) that can each coupleto a portion (e.g., memory unit) of parallel processor memory 222. Inone implementation, the number of partition units 220A-220N isconfigured to be equal to the number of memory units, such that a firstpartition unit 220A has a corresponding first memory unit 224A, a secondpartition unit 220B has a corresponding memory unit 224B, and an Nthpartition unit 220N has a corresponding Nth memory unit 224N. In otherembodiments, the number of partition units 220A-220N may not be equal tothe number of memory devices.

In various embodiments, the memory units 224A-224N can include varioustypes of memory devices, including dynamic random access memory (DRAM)or graphics random access memory, such as synchronous graphics randomaccess memory (SGRAM), including graphics double data rate (GDDR)memory. In one embodiment, the memory units 224A-224N may also include3D stacked memory, including but not limited to high bandwidth memory(HBM). Persons skilled in the art will appreciate that the specificimplementation of the memory units 224A-224N can vary, and can beselected from one of various conventional designs. Render targets, suchas frame buffers or texture maps may be stored across the memory units224A-224N, allowing partition units 220A-220N to write portions of eachrender target in parallel to efficiently use the available bandwidth ofparallel processor memory 222. In some embodiments, a local instance ofthe parallel processor memory 222 may be excluded in favor of a unifiedmemory design that utilizes system memory in conjunction with localcache memory.

In one embodiment, any one of the clusters 214A-214N of the processingcluster array 212 can process data that will be written to any of thememory units 224A-224N within parallel processor memory 222. The memorycrossbar 216 can be configured to transfer the output of each cluster214A-214N to any partition unit 220A-220N or to another cluster214A-214N, which can perform additional processing operations on theoutput. Each cluster 214A-214N can communicate with the memory interface218 through the memory crossbar 216 to read from or write to variousexternal memory devices. In one embodiment, the memory crossbar 216 hasa connection to the memory interface 218 to communicate with the I/Ounit 204, as well as a connection to a local instance of the parallelprocessor memory 222, enabling the processing units within the differentprocessing clusters 214A-214N to communicate with system memory or othermemory that is not local to the parallel processing unit 202. In oneembodiment, the memory crossbar 216 can use virtual channels to separatetraffic streams between the clusters 214A-214N and the partition units220A-220N.

While a single instance of the parallel processing unit 202 isillustrated within the parallel processor 200, any number of instancesof the parallel processing unit 202 can be included. For example,multiple instances of the parallel processing unit 202 can be providedon a single add-in card, or multiple add-in cards can be interconnected.The different instances of the parallel processing unit 202 can beconfigured to inter-operate even if the different instances havedifferent numbers of processing cores, different amounts of localparallel processor memory, and/or other configuration differences. Forexample, and in one embodiment, some instances of the parallelprocessing unit 202 can include higher precision floating point unitsrelative to other instances. Systems incorporating one or more instancesof the parallel processing unit 202 or the parallel processor 200 can beimplemented in a variety of configurations and form factors, includingbut not limited to desktop, laptop, or handheld personal computers,servers, workstations, game consoles, and/or embedded systems.

FIG. 2B is a block diagram of a partition unit 220 according to anexemplary embodiment. In one embodiment, the partition unit 220 is aninstance of one of the partition units 220A-220N of FIG. 2A. Asillustrated, the partition unit 220 includes an L2 cache 221, a framebuffer interface 225, and a ROP 226 (raster operations unit). The L2cache 221 is a read/write cache that is configured to perform load andstore operations received from the memory crossbar 216 and ROP 226. Readmisses and urgent write-back requests are output by L2 cache 221 toframe buffer interface 225 for processing. Updates can also be sent tothe frame buffer via the frame buffer interface 225 for processing. Inone embodiment, the frame buffer interface 225 interfaces with one ofthe memory units in parallel processor memory, such as the memory units224A-224N of FIG. 2A (e.g., within parallel processor memory 222).

In graphics applications, the ROP 226 is a processing unit that performsraster operations such as stencil, z test, blending, and the like. TheROP 226 then outputs processed graphics data that is stored in graphicsmemory. In some embodiments, the ROP 226 includes compression logic tocompress depth or color data that is written to memory and decompressdepth or color data that is read from memory. The compression logic canbe lossless compression logic that makes use of one or more of multiplecompression algorithms. The type of compression that is performed by theROP 226 can vary based on the statistical characteristics of the data tobe compressed. For example, in one embodiment, delta color compressionis performed on depth and color data on a per-tile basis.

In some embodiments, the ROP 226 is included within each processingcluster (e.g., cluster 214A-214N of FIG. 2A) instead of within thepartition unit 220. In one such embodiment, read and write requests forpixel data are transmitted over the memory crossbar 216 instead of pixelfragment data. The processed graphics data may be displayed on a displaydevice, such as one of the one or more display device(s) 110A and 110Bof FIG. 1 , routed for further processing by the processor(s) 102, orrouted for further processing by one of the processing entities withinthe parallel processor 200 of FIG. 2A.

FIG. 2C is a block diagram of a processing cluster 214 within a parallelprocessing unit according to an exemplary embodiment. In one embodiment,the processing cluster is an instance of one of the processing clusters214A-214N of FIG. 2A. The processing cluster 214 can be configured toexecute many threads in parallel, where the term “thread” refers to aninstance of a particular program executing on a particular set of inputdata. In some embodiments, single-instruction, multiple-data (SIMD)instruction issue techniques are used to support parallel execution of alarge number of threads without providing multiple independentinstruction units. In other embodiments, single-instruction,multiple-thread (SIMT) techniques are used to support parallel executionof a large number of generally synchronized threads, using a commoninstruction unit configured to issue instructions to a set of processingengines within each one of the processing clusters. Unlike a SIMDexecution regime, where all processing engines typically executeidentical instructions, SIMT execution allows different threads to morereadily follow divergent execution paths through a given thread program.Persons skilled in the art will understand that a SIMD processing regimerepresents a functional subset of a SIMT processing regime.

Operation of the processing cluster 214 can be controlled via a pipelinemanager 232 that distributes processing tasks to SIMT parallelprocessors. The pipeline manager 232 receives instructions from thescheduler 210 of FIG. 2A and manages execution of those instructions viaa graphics multiprocessor 234 and/or a texture unit 236. The illustratedgraphics multiprocessor 234 is an exemplary instance of a SIMT parallelprocessor. However, various types of SIMT parallel processors ofdiffering architectures may be included within the processing cluster214. One or more instances of the graphics multiprocessor 234 can beincluded within a processing cluster 214. The graphics multiprocessor234 can process data and a data crossbar 240 can be used to distributethe processed data to one of multiple possible destinations, includingother shader units. The pipeline manager 232 can facilitate thedistribution of processed data by specifying destinations for processeddata to be distributed vis the data crossbar 240.

Each graphics multiprocessor 234 within the processing cluster 214 caninclude an identical set of functional execution logic (e.g., arithmeticlogic units, load-store units, etc.). The functional execution logic canbe configured in a pipelined manner in which new instructions can beissued before previous instructions are complete. The functionalexecution logic supports a variety of operations including integer andfloating point arithmetic, comparison operations, Boolean operations,bit-shifting, and computation of various algebraic functions. In oneembodiment, the same functional-unit hardware can be leveraged toperform different operations and any combination of functional units maybe present.

The instructions transmitted to the processing cluster 214 constitutes athread. A set of threads executing across the set of parallel processingengines is a thread group. A thread group executes the same program ondifferent input data. Each thread within a thread group can be assignedto a different processing engine within a graphics multiprocessor 234. Athread group may include fewer threads than the number of processingengines within the graphics multiprocessor 234. When a thread groupincludes fewer threads than the number of processing engines, one ormore of the processing engines may be idle during cycles in which thatthread group is being processed. A thread group may also include morethreads than the number of processing engines within the graphicsmultiprocessor 234. When the thread group includes more threads than thenumber of processing engines within the graphics multiprocessor 234,processing can be performed over consecutive clock cycles. In oneembodiment, multiple thread groups can be executed concurrently on agraphics multiprocessor 234.

In one embodiment, the graphics multiprocessor 234 includes an internalcache memory to perform load and store operations. In one embodiment,the graphics multiprocessor 234 can forego an internal cache and use acache memory (e.g., L1 cache 248) within the processing cluster 214.Each graphics multiprocessor 234 also has access to L2 caches within thepartition units (e.g., partition units 220A-220N of FIG. 2A) that areshared among all processing clusters 214 and may be used to transferdata between threads. The graphics multiprocessor 234 may also accessoff-chip global memory, which can include one or more of local parallelprocessor memory and/or system memory. Any memory external to theparallel processing unit 202 may be used as global memory. Embodimentsin which the processing cluster 214 includes multiple instances of thegraphics multiprocessor 234 can share common instructions and data,which may be stored in the L1 cache 248.

Each processing cluster 214 may include an MMU 245 (memory managementunit) that is configured to map virtual addresses into physicaladdresses. In other embodiments, one or more instances of the MMU 245may reside within the memory interface 218 of FIG. 2A. The MMU 245includes a set of page table entries (PTEs) used to map a virtualaddress to a physical address of a tile (talk more about tiling) andoptionally a cache line index. The MMU 245 may include addresstranslation lookaside buffers (TLB) or caches that may reside within thegraphics multiprocessor 234 or the L1 cache or processing cluster 214.The physical address is processed to distribute surface data accesslocality to allow efficient request interleaving among partition units.The cache line index may be used to determine whether a request for acache line is a hit or miss.

In graphics and computing applications, a processing cluster 214 may beconfigured such that each graphics multiprocessor 234 is coupled to atexture unit 236 for performing texture mapping operations, e.g.,determining texture sample positions, reading texture data, andfiltering the texture data. Texture data is read from an internaltexture L1 cache (not shown) or in some embodiments from the L1 cachewithin graphics multiprocessor 234 and is fetched from an L2 cache,local parallel processor memory, or system memory, as needed. Eachgraphics multiprocessor 234 outputs processed tasks to the data crossbar240 to provide the processed task to another processing cluster 214 forfurther processing or to store the processed task in an L2 cache, localparallel processor memory, or system memory via the memory crossbar 216.A preROP 242 (pre-raster operations unit) is configured to receive datafrom graphics multiprocessor 234, direct data to ROP units, which may belocated with partition units as described herein (e.g., partition units220A-220N of FIG. 2A). The preROP 242 unit can perform optimizations forcolor blending, organize pixel color data, and perform addresstranslations.

It will be appreciated that the core architecture described herein isillustrative and that variations and modifications are possible. Anynumber of processing units, e.g., graphics multiprocessor 234, textureunits 236, preROPs 242, etc., may be included within a processingcluster 214. Further, while only one processing cluster 214 is shown, aparallel processing unit as described herein may include any number ofinstances of the processing cluster 214. In one embodiment, eachprocessing cluster 214 can be configured to operate independently ofother processing clusters 214 using separate and distinct processingunits, L1 caches, etc.

FIG. 2D shows a graphics multiprocessor 234 according to one exemplaryembodiment. In such embodiment, the graphics multiprocessor 234 coupleswith the pipeline manager 232 of the processing cluster 214. Thegraphics multiprocessor 234 has an execution pipeline including but notlimited to an instruction cache 252, an instruction unit 254, an addressmapping unit 256, a register file 258, one or more general purposegraphics processing unit (GPGPU) cores 262, and one or more load/storeunits 266. The GPGPU cores 262 and load/store units 266 are coupled withcache memory 272 and shared memory 270 via a memory and cacheinterconnect 268.

In one embodiment, the instruction cache 252 receives a stream ofinstructions to execute from the pipeline manager 232. The instructionsare cached in the instruction cache 252 and dispatched for execution bythe instruction unit 254. The instruction unit 254 can dispatchinstructions as thread groups (e.g., warps), with each thread of thethread group assigned to a different execution unit within GPGPU core262. An instruction can access any of a local, shared, or global addressspace by specifying an address within a unified address space. Theaddress mapping unit 256 can be used to translate addresses in theunified address space into a distinct memory address that can beaccessed by the load/store units 266.

The register file 258 provides a set of registers for the functionalunits of the graphics multiprocessor 234. The register file 258 providestemporary storage for operands connected to the data paths of thefunctional units (e.g., GPGPU cores 262, load/store units 266) of thegraphics multiprocessor 234. In one embodiment, the register file 258 isdivided between each of the functional units such that each functionalunit is allocated a dedicated portion of the register file 258. In oneembodiment, the register file 258 is divided between the different warpsbeing executed by the graphics multiprocessor 234.

The GPGPU cores 262 can each include floating point units (FPUs) and/orinteger arithmetic logic units (ALUs) that are used to executeinstructions of the graphics multiprocessor 234. The GPGPU cores 262 canbe similar in architecture or can differ in architecture, according toembodiments. For example, and in one embodiment, a first portion of theGPGPU cores 262 includes a single precision FPU and an integer ALU whilea second portion of the GPGPU cores includes a double precision FPU. Inone embodiment, the FPUs can implement the IEEE 754-2008 standard forfloating point arithmetic or enable variable precision floating pointarithmetic. The graphics multiprocessor 234 can additionally include oneor more fixed function or special function units to perform specificfunctions such as copy rectangle or pixel blending operations. In oneembodiment one or more of the GPGPU cores can also include fixed orspecial function logic.

In one embodiment, the GPGPU cores 262 include SIMD logic capable ofperforming a single instruction on multiple sets of data. In oneembodiment GPGPU cores 262 can physically execute SIMD4, SIMD8, andSIMD16 instructions and logically execute SIMD1, SIMD2, and SIMD32instructions. The SIMD instructions for the GPGPU cores can be generatedat compile time by a shader compiler or automatically generated whenexecuting programs written and compiled for single program multiple data(SPMD) or SIMT architectures. Multiple threads of a program configuredfor the SIMT execution model can executed via a single SIMI)instruction. For example, and in one embodiment, eight SIMT threads thatperform the same or similar operations can be executed in parallel via asingle SIMD8 logic unit.

The memory and cache interconnect 268 is an interconnect network thatconnects each of the functional units of the graphics multiprocessor 234to the register file 258 and to the shared memory 270. In oneembodiment, the memory and cache interconnect 268 is a crossbarinterconnect that allows the load/store unit 266 to implement load andstore operations between the shared memory 270 and the register file258. The register file 258 can operate at the same frequency as theGPGPU cores 262, thus data transfer between the GPGPU cores 262 and theregister file 258 is very low latency. The shared memory 270 can be usedto enable communication between threads that execute on the functionalunits within the graphics multiprocessor 234. The cache memory 272 canbe used as a data cache for example, to cache texture data communicatedbetween the functional units and the texture unit 236. The shared memory270 can also be used as a program managed cache. Threads executing onthe GPGPU cores 262 can programmatically store data within the sharedmemory in addition to the automatically cached data that is storedwithin the cache memory 272.

FIGS. 3A-3B illustrate additional graphics multiprocessors according toexemplary embodiments. The illustrated graphics multiprocessors 325, 350are variants of the graphics multiprocessor 234 of FIGS. 2C-2D. Theillustrated graphics multiprocessors 325, 350 can be configured as astreaming multiprocessor (SM) capable of simultaneous execution of alarge number of execution threads.

FIG. 3A shows a graphics multiprocessor 325 according to an additionalexemplary embodiment. The graphics multiprocessor 325 includes multipleadditional instances of execution resource units relative to thegraphics multiprocessor 234 of FIGS. 2C-2D. For example, the graphicsmultiprocessor 325 can include multiple instances of the instructionunit 332A-332B, register file 334A-334B, and texture unit(s) 344A-344B.The graphics multiprocessor 325 also includes multiple sets of graphicsor compute execution units (e.g., GPGPU core 336A-336B, GPGPU core337A-337B, GPGPU core 338A-338B) and multiple sets of load/store units340A-340B. In one embodiment, the execution resource units have a commoninstruction cache 330, texture and/or data cache memory 342, and sharedmemory 346.

The various components can communicate via an interconnect fabric 327.In one embodiment, the interconnect fabric 327 includes one or morecrossbar switches to enable communication between the various componentsof the graphics multiprocessor 325. In one embodiment, the interconnectfabric 327 is a separate, high-speed network fabric layer upon whicheach component of the graphics multiprocessor 325 is stacked. Thecomponents of the graphics multiprocessor 325 communicate with remotecomponents via the interconnect fabric 327. For example, the GPGPU cores336A-336B, 337A-337B, and 338A-338B can each communicate with sharedmemory 346 via the interconnect fabric 327. The interconnect fabric 327can arbitrate communication within the graphics multiprocessor 325 toensure a fair bandwidth allocation between components.

FIG. 3B shows a graphics multiprocessor 350 according to an additionalexemplary embodiment. The graphics processor includes multiple sets ofexecution resources 356A-356D, where each set of execution resourceincludes multiple instruction units, register files, GPGPU cores, andload store units, as illustrated in FIG. 2D and FIG. 3A. The executionresources 356A-356D can work in concert with texture unit(s) 360A-360Dfor texture operations, while sharing an instruction cache 354, andshared memory 362. In one embodiment, the execution resources 356A-356Dcan share an instruction cache 354 and shared memory 362, as well asmultiple instances of a texture and/or data cache memory 358A-35813. Thevarious components can communicate via an interconnect fabric 352similar to the interconnect fabric 327 of FIG. 3A.

Persons skilled in the art will understand that the architecturedescribed in FIGS. 1, 2A-2D, and 3A-3B are descriptive and not limitingas to the scope of the present embodiments, which are exemplary. Thus,the techniques described herein may be implemented on any properlyconfigured processing unit, including, without limitation, one or moremobile application processors, one or more desktop or server centralprocessing units (CPUs) including multi-core CPUs, one or more parallelprocessing units, such as the parallel processing unit 202 of FIG. 2A,as well as one or more graphics processors or special purpose processingunits, without departure from the scope of the embodiments describedherein.

In some embodiments, a parallel processor or GPGPU as described hereinis communicatively coupled to host/processor cores to accelerategraphics operations, machine-learning operations, pattern analysisoperations, and various general purpose GPU (GPGPU) functions. The GPUmay be communicatively coupled to the host processor/cores over a bus orother interconnect (e.g., a high speed interconnect such as PCIe orNVLink). In other embodiments, the GPU may be integrated on the samepackage or chip as the cores and communicatively coupled to the coresover an internal processor bus/interconnect (i.e., internal to thepackage or chip). Regardless of the manner in which the GPU isconnected, the processor cores may allocate work to the GPU) in the formof sequences of commands/instructions contained in a work descriptor.The GPU then uses dedicated circuitry/logic for efficiently processingthese commands/instructions.

Techniques for GPU to Host Processor Interconnection

FIG. 4A illustrates an exemplary architecture in which a plurality ofGPUs 410-413 are communicatively coupled to a plurality of multi-coreprocessors 405-406 over high-speed links 429, 440, 442, and 443 (e.g.,buses, point-to-point interconnects, etc.). In one embodiment, thehigh-speed links 429, 440, 442, and 443 support a communicationthroughput of 4 GB/s, 30 GB/s, 80 GB/s or higher, depending on theimplementation. Various interconnect protocols may be used including,but not limited to, PCIe 4.0 or 5.0 and NVLink 2.0. However, theunderlying principles of the invention are not limited to any particularcommunication protocol or throughput.

In addition, and in one embodiment, two or more of the GPUs 410-413 areinterconnected over high-speed links 444 and 449, which may beimplemented using the same or different protocols/links than those usedfor high-speed links 429, 440, 442, and 443. Similarly, two or more ofthe multi-core processors 405-406 may be connected over high speed link433 which may be symmetric multi-processor (SMP) buses operating at 20GB/s, 30 GB/s, 120 GB/s or higher. Alternatively, all communicationbetween the various system components shown in FIG. 4A may beaccomplished using the same protocols/links (e.g., over a commoninterconnection fabric). As mentioned, however, the underlyingprinciples of the invention are not limited to any particular type ofinterconnect technology.

In one embodiment, each multi-core processor 405-406 is communicativelycoupled to a processor memory 401-402, via memory interconnects 430-431,respectively, and each GPU 410-413 is communicatively coupled to GPUmemory 420-423 over GPU memory interconnects 450-453, respectively. Thememory interconnects 430-431 and 450-453 may utilize the same ordifferent memory access technologies. By way of example, and notlimitation, the processor memories 401-402 and GPU memories 420-423 maybe volatile memories such as dynamic random access memories (DRAMs)(including stacked DRAMs), Graphics DDR SDRAM (GDDR) (e.g., GDDR5,GDDR6), or High Bandwidth Memory (HBM) and/or may be non-volatilememories such as 3D XPoint or Nano-Ram. In one embodiment, some portionof the memories may be volatile memory and another portion may benon-volatile memory (e.g., using a two-level memory (2LM) hierarchy).

As described below, although the various processors 405-406 and GPUs410-413 may be physically coupled to a particular memory 401-402,420-423, respectively, a unified memory architecture may be implementedin which the same virtual system address space (also referred to as the“effective address” space) is distributed among all of the variousphysical memories. For example, processor memories 401-402 may eachcomprise 64 GB of the system memory address space and GPU memories420-423 may each comprise 32 GB of the system memory address space(resulting in a total of 256 GB addressable memory in this example).

FIG. 4B illustrates additional details for an interconnection between amulti-core processor 407 and a graphics acceleration module 446 inaccordance with one exemplary embodiment. The graphics accelerationmodule 446 may include one or more GPU chips integrated on a line cardwhich is coupled to the processor 407 via the high-speed link 440.Alternatively, the graphics acceleration module 446 may be integrated onthe same package or chip as the processor 407.

The illustrated processor 407 includes a plurality of cores 460A-460D,each with a translation lookaside buffer 461A-461D and one or morecaches 462A-462D. The cores may include various other components forexecuting instructions and processing data which are not illustrated toavoid obscuring the underlying principles of the invention (e.g.,instruction fetch units, branch prediction units, decoders, executionunits, reorder buffers, etc.). The caches 462A-462D may comprise level 1(L1) and level 2 (L2) caches. In addition, one or more shared caches426456 may be included in the caching hierarchy and shared by sets ofthe cores 460A-460D. For example, one embodiment of the processor 407includes 24 cores, each with its own L1 cache, twelve shared L2 caches,and twelve shared L3 caches. In this embodiment, one of the L2 and L3caches are shared by two adjacent cores. The processor 407 and thegraphics accelerator integration module 446 connect with system memory441, which may include processor memories 401-402.

Coherency is maintained for data and instructions stored in the variouscaches 462A-462D, 456 and system memory 441 via inter-core communicationover a coherence bus 464. For example, each cache may have cachecoherency logic/circuitry associated therewith to communicate to overthe coherence bus 464 in response to detected reads or writes toparticular cache lines. In one implementation, a cache snooping protocolis implemented over the coherence bus 464 to snoop cache accesses. Cachesnooping/coherency techniques are well understood by those of skill inthe art and will not be described in detail here to avoid obscuring theunderlying principles of the invention.

In one embodiment, a proxy circuit 425 communicatively couples thegraphics acceleration module 446 to the coherence bus 464, allowing thegraphics acceleration module 446 to participate in the cache coherenceprotocol as a peer of the cores. In particular, an interface 435provides connectivity to the proxy circuit 425 over high-speed link 440(e.g., a bus, NVLink, etc.) and an interface 437 connects the graphicsacceleration module 446 to the link 440.

In one implementation, an accelerator integration circuit 436 providescache management, memory access, context management, and interruptmanagement services on behalf of a plurality of graphics processingengines 431, 432, N of the graphics acceleration module 446. Thegraphics processing engines 431, 432, N may each comprise a separategraphics processing unit (GPU). Alternatively, the graphics processingengines 431, 432, N may comprise different types of graphics processingengines within a GPU such as graphics execution units, media processingengines (e.g., video encoders/decoders), samplers, and blit engines. Inother words, the graphics acceleration module may be a GPU with aplurality of graphics processing engines 431-432, N or the graphicsprocessing engines 431-432, N may be individual CPUs integrated on acommon package, line card, or chip.

In one embodiment, the accelerator integration circuit 436 includes amemory management unit (MMU) 439 for performing various memorymanagement functions such as virtual-to-physical memory translations(also referred to as effective-to-real memory translations) and memoryaccess protocols for accessing system memory 441. The MMU 439 may alsoinclude a translation lookaside buffer (TLB) (not shown) for caching thevirtual/effective to physical/real address translations. In oneimplementation, a cache 438 stores commands and data for efficientaccess by the graphics processing engines 431-432, N. In one embodiment,the data stored in cache 438 and graphics memories 433-434, N is keptcoherent with the core caches 462A-462D, 456 and system memory 441. Asmentioned, this may be accomplished via proxy circuit 425 which takespart in the cache coherency mechanism on behalf of cache 438 andmemories 433-434, N (e.g., sending updates to the cache 438 related tomodifications/accesses of cache lines on processor caches 462A-462D, 456and receiving updates from the cache 438).

A set of registers 445 store context data for threads executed by thegraphics processing engines 431-432, N and a context management circuit448 manages the thread contexts. For example, the context managementcircuit 448 may perform save and restore operations to save and restorecontexts of the various threads during contexts switches (e.g., where afirst thread is saved and a second thread is stored so that the secondthread can be executed by a graphics processing engine). For example, ona context switch, the context management circuit 448 may store currentregister values to a designated region in memory (e.g., identified by acontext pointer). It may then restore the register values when returningto the context. In one embodiment, an interrupt management circuit 447receives and processes interrupts received from system devices.

In one implementation, virtual/effective addresses from a graphicsprocessing engine 431 are translated to real/physical addresses insystem memory 441 by the MMU 439. One embodiment of the acceleratorintegration circuit 436 supports multiple (e.g., 4, 8, 16) graphicsaccelerator modules 446 and/or other accelerator devices. The graphicsaccelerator module 446 may be dedicated to a single application executedon the processor 407 or may be shared between multiple applications. Inone embodiment, a virtualized graphics execution environment ispresented in which the resources of the graphics processing engines431-432, N are shared with multiple applications or virtual machines(VMs). The resources may be subdivided into “slices” which are allocatedto different VMs and/or applications based on the processingrequirements and priorities associated with the VMs and/or applications.

Thus, the accelerator integration circuit acts as a bridge to the systemfor the graphics acceleration module 446 and provides addresstranslation and system memory cache services. In addition, theaccelerator integration circuit 436 may provide virtualizationfacilities for the host processor to manage virtualization of thegraphics processing engines, interrupts, and memory management.

Because hardware resources of the graphics processing engines 431-432, Nare mapped explicitly to the real address space seen by the hostprocessor 407, any host processor can address these resources directlyusing an effective address value. One function of the acceleratorintegration circuit 436, in one embodiment, is the physical separationof the graphics processing engines 431-432, N so that they appear to thesystem as independent units.

As mentioned, in the illustrated embodiment, one or more graphicsmemories 433-434, M are coupled to each of the graphics processingengines 431-432, N, respectively. The graphics memories 433-434, M storeinstructions and data being processed by each of the graphics processingengines 431-432, N. The graphics memories 433-434, M may be volatilememories such as DRAMs (including stacked DRAMs), GDDR memory (e.g.,GDDR5, GDDR6), or HBM, and/or may be non-volatile memories such as 3DXPoint or Nano-Ram.

In one embodiment, to reduce data traffic over link 440, biasingtechniques are used to ensure that the data stored in graphics memories433-434, M is data which will be used most frequently by the graphicsprocessing engines 431-432, N and preferably not used by the cores460A-460D (at least not frequently). Similarly, the biasing mechanismattempts to keep data needed by the cores (and preferably not thegraphics processing engines 431-432, N) within the caches 462A-462D, 456of the cores and system memory 441.

FIG. 4C illustrates another exemplary embodiment in which theaccelerator integration circuit 436 is integrated within the processor407. In this embodiment, the graphics processing engines 431-432, Ncommunicate directly over the high-speed link 440 to the acceleratorintegration circuit 436 via interface 437 and interface 435 (which,again, may be utilize any form of bus or interface protocol). Theaccelerator integration circuit 436 may perform the same operations asthose described with respect to FIG. 4B, but potentially at a higherthroughput given its close proximity to the coherency bus 464 and caches462A-462D, 426.

One embodiment supports different programming models including adedicated-process programming model (no graphics acceleration modulevirtualization) and shared programming models (with virtualization). Thelatter may include programming models which are controlled by theaccelerator integration circuit 436 and programming models which arecontrolled by the graphics acceleration module 446.

In one embodiment of the dedicated process model, graphics processingengines 431-432, N are dedicated to a single application or processunder a single operating system. The single application can funnel otherapplication requests to the graphics engines 431-432, N, providingvirtualization within a VM/partition.

In the dedicated-process programming models, the graphics processingengines 431-432, N, may be shared by multiple VIM/applicationpartitions. The shared models require a system hypervisor to virtualizethe graphics processing engines 431-432, N to allow access by eachoperating system. For single-partition systems without a hypervisor, thegraphics processing engines 431-432, N are owned by the operatingsystem. In both cases, the operating system can virtualize the graphicsprocessing engines 431-432, N to provide access to each process orapplication.

For the shared programming model, the graphics acceleration module 446or an individual graphics processing engine 431-432, N selects a processelement using a process handle. In one embodiment, process elements arestored in system memory 441 and are addressable using the effectiveaddress to real address translation techniques described herein. Theprocess handle may be an implementation-specific value provided to thehost process when registering its context with the graphics processingengine 431-432, N (that is, calling system software to add the processelement to the process element linked list). The lower 16-bits of theprocess handle may be the offset of the process element within theprocess element linked list.

FIG. 4D illustrates an exemplary accelerator integration slice 490. Asused herein, a “slice” comprises a specified portion of the processingresources of the accelerator integration circuit 436. Applicationeffective address space 482 within system memory 441 stores processelements 483. In one embodiment, the process elements 483 are stored inresponse to GPU invocations 481 from applications 480 executed on theprocessor 407. A process element 483 contains the process state for thecorresponding application 480. A work descriptor (WD) 484 contained inthe process element 483 can be a single job requested by an applicationor may contain a pointer to a queue of jobs. In the latter case, the WD484 is a pointer to the job request queue in the application's addressspace 482.

The graphics acceleration module 446 and/or the individual graphicsprocessing engines 431-432, N can be shared by all or a subset of theprocesses in the system. Embodiments of the invention include aninfrastructure for setting up the process state and sending a WD 484 toa graphics acceleration module 446 to start a job in a virtualizedenvironment.

In one implementation, the dedicated-process programming model isimplementation-specific. In this model, a single process owns thegraphics acceleration module 446 or an individual graphics processingengine 431. Because the graphics acceleration module 446 is owned by asingle process, the hypervisor initializes the accelerator integrationcircuit 436 for the owning partition and the operating systeminitializes the accelerator integration circuit 436 for the owningprocess at the time when the graphics acceleration module 446 isassigned.

In operation, a WD fetch unit 491 in the accelerator integration slice490 fetches the next WD 484 which includes an indication of the work tobe done by one of the graphics processing engines of the graphicsacceleration module 446. Data from the WD 484 may be stored in registers445 and used by the MMU 439, interrupt management circuit 447 and/orcontext management circuit 448 as illustrated. For example, oneembodiment of the MMU 439 includes segment/page walk circuitry foraccessing segment/page tables 486 within the OS virtual address space485. The interrupt management circuit 447 may process interrupt events492 received from the graphics acceleration module 446. When performinggraphics operations, an effective address 493 generated by a graphicsprocessing engine 431-432, N is translated to a real address by the MMU439.

In one embodiment, the same set of registers 445 are duplicated for eachgraphics processing engine 431-432, N and/or graphics accelerationmodule 446 and may be initialized by the hypervisor or operating system.Each of these duplicated registers may be included in an acceleratorintegration slice 490. Exemplary registers that may be initialized bythe hypervisor are shown in Table 1.

TABLE 1 Hypervisor Initialized Registers 1 Slice Control Register 2 RealAddress (RA) Scheduled Processes Area Pointer 3 Authority Mask OverrideRegister 4 Interrupt Vector Table Entry Offset 5 Interrupt Vector TableEntry Limit 6 State Register 7 Logical Partition ID 8 Real address (RA)Hypervisor Accelerator Utilization Record Pointer 9 Storage DescriptionRegister

Exemplary registers that may be initialized by the operating system areshown in Table 2.

TABLE 2 Operating System Initialized Registers 1 Process and ThreadIdentification 2 Effective Address (EA) Context Save/Restore Pointer 3Virtual Address (VA) Accelerator Utilization Record Pointer 4 VirtualAddress (VA) Storage Segment Table Pointer 5 Authority Mask 6 Workdescriptor

In one embodiment, each WD 484 is specific to a particular graphicsacceleration module 446 and/or graphics processing engine 431-432, N. Itcontains all the information a graphics processing engine 431-432, Nrequires to do its work or it can be a pointer to a memory locationwhere the application has set up a command queue of work to becompleted.

FIG. 4E illustrates additional details for one exemplary embodiment of ashared model. This embodiment includes a hypervisor real address space498 in which a process element list 499 is stored. The hypervisor realaddress space 498 is accessible via a hypervisor 496 which virtualizesthe graphics acceleration module engines for the operating system 495.

The shared programming models allow for all or a subset of processesfrom all or a subset of partitions in the system to use a graphicsacceleration module 446. There are two programming models where thegraphics acceleration module 446 is shared by multiple processes andpartitions: time-sliced shared and graphics directed shared.

In this model, the system hypervisor 496 owns the graphics accelerationmodule 446 and makes its function available to all operating systems495. For a graphics acceleration module 446 to support virtualization bythe system hypervisor 496, the graphics acceleration module 446 mayadhere to the following requirements: 1) An application's job requestmust be autonomous (that is, the state does not need to be maintainedbetween jobs), or the graphics acceleration module 446 must provide acontext save and restore mechanism. 2) An application's job request isguaranteed by the graphics acceleration module 446 to complete in aspecified amount of time, including any translation faults, or thegraphics acceleration module 446 provides the ability to preempt theprocessing of the job. 3) The graphics acceleration module 446 must beguaranteed fairness between processes when operating in the directedshared programming model.

In one embodiment, for the shared model, the application 480 is requiredto make an operating system 495 system call with a graphics accelerationmodule 446 type, a work descriptor (WD), an authority mask register(AMR) value, and a context save/restore area pointer (CSRP). Thegraphics acceleration module 446 type describes the targetedacceleration function for the system call. The graphics accelerationmodule 446 type may be a system-specific value. The WD is formattedspecifically for the graphics acceleration module 446 and can be in theform of a graphics acceleration module 446 command, an effective addresspointer to a user-defined structure, an effective address pointer to aqueue of commands, or any other data structure to describe the work tobe done by the graphics acceleration module 446. In one embodiment, theAMR value is the AMR state to use for the current process. The valuepassed to the operating system is similar to an application setting theAMR. If the accelerator integration circuit 436 and graphicsacceleration module 446 implementations do not support a User AuthorityMask Override Register (UAMOR), the operating system may apply thecurrent UAMOR value to the AMR value before passing the AMR in thehypervisor call. The hypervisor 496 may optionally apply the currentAuthority Mask Override Register (AMOR) value before placing the AMRinto the process element 483, In one embodiment, the CSRP is one of theregisters 445 containing the effective address of an area in theapplication's address space 482 for the graphics acceleration module 446to save and restore the context state. This pointer is optional if nostate is required to be saved between jobs or when a job is preempted.The context save/restore area may be pinned system memory.

Upon receiving the system call, the operating system 495 may verify thatthe application 480 has registered and been given the authority to usethe graphics acceleration module 446. The operating system 495 thencalls the hypervisor 496 with the information shown in Table 3.

TABLE 3 OS to Hypervisor Call Parameters 1 A work descriptor (WD) 2 AnAuthority Mask Register (AMR) value (potentially masked). 3 An effectiveaddress (EA) Context Save/Restore Area Pointer (CSRP) 4 A process ID(PID) and optional thread ID (TID) 5 A virtual address (VA) acceleratorutilization record pointer (AURP) 6 The virtual address of the storagesegment table poi nter (SSTP) 7 A logical interrupt service number(LISN)

Upon receiving the hypervisor call, the hypervisor 496 verifies that theoperating system 495 has registered and been given the authority to usethe graphics acceleration module 446. The hypervisor 496 then puts theprocess element 483 into the process element linked list for thecorresponding graphics acceleration module 446 type. The process elementmay include the information shown in Table 4.

TABLE 4 Process Element Information 1 A work descriptor (WD) 2 AnAuthority Mask Register (AMR) value (potentially masked). 3 An effectiveaddress (EA) Context Save/Restore Area Pointer (CSRP) 4 A process ID(PID) and optional thread ID (TID) 5 A virtual address (VA) acceleratorutilization record pointer (AURP) 6 The virtual address of the storagesegment table pointer (SSTP) 7 A logical interrupt service number (LISN)8 Interrupt vector table, derived from the hypervisor call parameters. 9A state register (SR) value 10 A logical partition ID (LPID) 11 A realaddress (RA) hypervisor accelerator utilization record pointer 12 TheStorage Descriptor Register (SDR)

In one embodiment, the hypervisor initializes a plurality of acceleratorintegration slice 490 registers 445.

As illustrated in FIG. 4F, one exemplary embodiment of the inventionemploys a unified memory addressable via a common virtual memory addressspace used to access the physical processor memories 401-402 and GPUmemories 420-423. In this implementation, operations executed on theGPUs 410-413 utilize the same virtual/effective memory address space toaccess the processors memories 401-402 and vice versa, therebysimplifying programmability. In one embodiment, a first portion of thevirtual/effective address space is allocated to the processor memory401, a second portion to the second processor memory 402, a thirdportion to the GPU memory 420, and so on. The entire virtual/effectivememory space (sometimes referred to as the effective address space) isthereby distributed across each of the processor memories 401-402 andGPU memories 420-423, allowing any processor or GPU to access anyphysical memory with a virtual address mapped to that memory.

In one embodiment, bias/coherence management circuitry 494A-494E withinone or more of the MMUs 439A-439E ensures cache coherence between thecaches of the host processors (e.g., 405) and the GPUs 410-413 andimplements biasing techniques indicating the physical memories in whichcertain types of data should be stored. While multiple instances ofbias/coherence management circuitry 494A-494E are illustrated in FIG.4F, the bias/coherence circuitry may be implemented within the MMU ofone or more host processors 405 and/or within the acceleratorintegration circuit 436.

One embodiment allows GPU-attached memory 420-423 to be mapped as partof system memory, and accessed using shared virtual memory (SVM)technology, but without suffering the typical performance drawbacksassociated with full system cache coherence. The ability to GPU-attachedmemory 420-423 to be accessed as system memory without onerous cachecoherence overhead provides a beneficial operating environment for GPUoffload. This arrangement allows the host processor 405 software tosetup operands and access computation results, without the overhead oftradition I/O DMA data copies. Such traditional copies involve drivercalls, interrupts and memory mapped I/O (MMIO) accesses that are allinefficient relative to simple memory accesses. At the same time, theability to access GPU attached memory 420-423 without cache coherenceoverheads can be critical to the execution time of an offloadedcomputation. In cases with substantial streaming write memory traffic,for example, cache coherence overhead can significantly reduce theeffective write bandwidth seen by a GPU 410-413. The efficiency ofoperand setup, the efficiency of results access, and the efficiency ofGPU computation all play a role in determining the effectiveness of GPUoffload.

In one implementation, the selection of between GPU bias and hostprocessor bias is driven by a bias tracker data structure. A bias tablemay be used, for example, which may be a page-granular structurecontrolled at the granularity of a memory page) that includes 1 or 2bits per GPU-attached memory page. The bias table may be implemented ina stolen memory range of one or more GPU-attached memories 420-423, withor without a bias cache in the GPU 410-413 (e.g., to cachefrequently/recently used entries of the bias table). Alternatively, theentire bias table may be maintained within the GPU.

In one implementation, the bias table entry associated with each accessto the GPU-attached memory 420-423 is accessed prior the actual accessto the GPU memory, causing the following operations. First, localrequests from the GPU 410-413 that find their page in GPU bias areforwarded directly to a corresponding GPU memory 420-423. Local requestsfrom the GPU that find their page in host bias are forwarded to theprocessor 405 (e.g., over a high-speed link as discussed above). In oneembodiment, requests from the processor 405 that find the requested pagein host processor bias complete the request like a normal memory read.Alternatively, requests directed to a GPU-biased page may be forwardedto the GPU 410-413. The GPU may then transition the page to a hostprocessor bias if it is not currently using the page.

The bias state of a page can be changed either by a software-basedmechanism, a hardware-assisted software-based mechanism, or, for alimited set of cases, a purely hardware-based mechanism.

One mechanism for changing the bias state employs an API call (e.g.OpenCL), which, in turn, calls the GPU's device driver which, in turn,sends a message (or enqueues a command descriptor) to the GPU directingit to change the bias state and, for some transitions, perform a cacheflushing operation in the host. The cache flushing operation is requiredfor a transition from host processor 405 bias to GPU bias, but is notrequired for the opposite transition.

In one embodiment, cache coherency is maintained by temporarilyrendering GPU-biased pages uncacheable by the host processor 405. Toaccess these pages, the processor 405 may request access from the GPU410 which may or may not grant access right away, depending on theimplementation. Thus, to reduce communication between the processor 405and GPU 410 it is beneficial to ensure that GPU-biased pages are thosewhich are required by the GPU but not the host processor 405 and viceversa.

Graphics Processing Pipeline

FIG. 5 illustrates a graphics processing pipeline 500 according to anexemplary embodiment. In one embodiment, a graphics processor canimplement the illustrated graphics processing pipeline 500. The graphicsprocessor can be included within the parallel processing subsystems asdescribed herein, such as the parallel processor 200 of FIG. 2A, which,in one embodiment, is a variant of the parallel processor(s) 112 of FIG.1 . The various parallel processing systems can implement the graphicsprocessing pipeline 500 via one or more instances of the parallelprocessing unit (e.g., parallel processing unit 202 of FIG. 2A) asdescribed herein. For example, a shader unit (e.g., graphicsmultiprocessor 234 of FIGS. 2C-2D) may be configured to perform thefunctions of one or more of a vertex processing unit 504, a tessellationcontrol processing unit 508, a tessellation evaluation processing unit512, a geometry processing unit 516, and a fragment/pixel processingunit 524. The functions of data assembler 502, primitive assemblers 506,514, 518, tessellation unit 510, rasterizer 522, and raster operationsunit 526 may also be performed by other processing engines within aprocessing cluster (e.g., processing cluster 214 of FIG. 2A) and acorresponding partition unit (e.g., partition unit 220A-220N of FIG.2A). The graphics processing pipeline 500 may also be implemented usingdedicated processing units for one or more functions. In one embodiment,one or more portions of the graphics processing pipeline 500 can beperformed by parallel processing logic within a general purposeprocessor (e.g., CPU). In one embodiment, one or more portions of thegraphics processing pipeline 500 can access on-chip memory (e.g.,parallel processor memory 222 as in FIG. 2A) via a memory interface 528,which may be an instance of the memory interface 218 of FIG. 2A.

In one embodiment, the data assembler 502 is a processing unit thatcollects vertex data for surfaces and primitives. The data assembler 502then outputs the vertex data, including the vertex attributes, to thevertex processing unit 504. The vertex processing unit 504 is aprogrammable execution unit that executes vertex shader programs,lighting and transforming vertex data as specified by the vertex shaderprograms. The vertex processing unit 504 reads data that is stored incache, local or system memory for use in processing the vertex data andmay be programmed to transform the vertex data from an object-basedcoordinate representation to a world space coordinate space or anormalized device coordinate space.

A first instance of a primitive assembler 506 receives vertex attributesfrom the vertex processing unit 504. The primitive assembler 506readings stored vertex attributes as needed and constructs graphicsprimitives for processing by tessellation control processing unit 508.The graphics primitives include triangles, line segments, points,patches, and so forth, as supported by various graphics processingapplication programming interfaces (APIs).

The tessellation control processing unit 508 treats the input verticesas control points for a geometric patch. The control points aretransformed from an input representation from the patch (e.g., thepatch's bases) to a representation that is suitable for use in surfaceevaluation by the tessellation evaluation processing unit 512. Thetessellation control processing unit 508 can also compute tessellationfactors for edges of geometric patches. A tessellation factor applies toa single edge and quantifies a view-dependent level of detail associatedwith the edge. A tessellation unit 510 is configured to receive thetessellation factors for edges of a patch and to tessellate the patchinto multiple geometric primitives such as line, triangle, orquadrilateral primitives, which are transmitted to a tessellationevaluation processing unit 512. The tessellation evaluation processingunit 512 operates on parameterized coordinates of the subdivided patchto generate a surface representation and vertex attributes for eachvertex associated with the geometric primitives.

A second instance of a primitive assembler 514 receives vertexattributes from the tessellation evaluation processing unit 512, readingstored vertex attributes as needed, and constructs graphics primitivesfor processing by the geometry processing unit 516. The geometryprocessing unit 516 is a programmable execution unit that executesgeometry shader programs to transform graphics primitives received fromprimitive assembler 514 as specified by the geometry shader programs. Inone embodiment, the geometry processing unit 516 is programmed tosubdivide the graphics primitives into one or more new graphicsprimitives and calculate parameters used to rasterize the new graphicsprimitives.

In some embodiments, the geometry processing unit 516 can add or deleteelements in the geometry stream. The geometry processing unit 516outputs the parameters and vertices specifying new graphics primitivesto primitive assembler 518. The primitive assembler 518 receives theparameters and vertices from the geometry processing unit 516 andconstructs graphics primitives for processing by a viewport scale, cull,and clip unit 520. The geometry processing unit 516 reads data that isstored in parallel processor memory or system memory for use inprocessing the geometry data. The viewport scale, cull, and clip unit520 performs clipping, culling, and viewport scaling and outputsprocessed graphics primitives to a rasterizer 522.

The rasterizer 522 can perform depth culling and other depth-basedoptimizations. The rasterizer 522 also performs scan conversion on thenew graphics primitives to generate fragments and output those fragmentsand associated coverage data to the fragment/pixel processing unit 524.The fragment/pixel processing unit 524 is a programmable execution unitthat is configured to execute fragment shader programs or pixel shaderprograms. The fragment/pixel processing unit 524 transforming fragmentsor pixels received from rasterizer 522, as specified by the fragment orpixel shader programs. For example, the fragment/pixel processing unit524 may be programmed to perform operations included but not limited totexture mapping, shading, blending, texture correction and perspectivecorrection to produce shaded fragments or pixels that are output to araster operations unit 526. The fragment/pixel processing unit 524 canread data that is stored in either the parallel processor memory or thesystem memory for use when processing the fragment data. Fragment orpixel shader programs may be configured to shade at sample, pixel, tile,or other granularities depending on the sampling rate configured for theprocessing units.

The raster operations unit 526 is a processing unit that performs rasteroperations including, but not limited to stencil, z test, blending, andthe like, and outputs pixel data as processed graphics data to be storedin graphics memory (e.g., parallel processor memory 222 as in FIG. 2A,and/or system memory 104 as in FIG. 1 , to be displayed on the one ormore display device(s) 110A and 110B or for further processing by one ofthe one or more processor(s) 102 or parallel processor(s) 112. In someembodiments, the raster operations unit 526 is configured to compress zor color data that is written to memory and decompress z or color datathat is read from memory.

Machine Learning Overview

A machine learning algorithm is an algorithm that can learn based on aset of data. Embodiments of machine learning algorithms can be designedto model high-level abstractions within a data set. For example, imagerecognition algorithms can be used to determine which of severalcategories to which a given input belong; regression algorithms canoutput a numerical value given an input; and pattern recognitionalgorithms can be used to generate translated text or perform text tospeech and/or speech recognition.

An exemplary type of machine learning algorithm is a neural network.There are many types of neural networks; a simple type of neural networkis a feedforward network. A feedforward network may be implemented as anacyclic graph in which the nodes are arranged in layers. Typically, afeedforward network topology includes an input layer and an output layerthat are separated by at least one hidden layer. The hidden layertransforms input received by the input layer into a representation thatis useful for generating output in the output layer. The network nodesare fully connected via edges to the nodes in adjacent layers, but thereare no edges between nodes within each layer. Data received at the nodesof an input layer of a feedforward network are propagated (i.e., “fedforward”) to the nodes of the output layer via an activation functionthat calculates the states of the nodes of each successive layer in thenetwork based on coefficients (“weights”) respectively associated witheach of the edges connecting the layers. Depending on the specific modelbeing represented by the algorithm being executed, the output from theneural network algorithm can take various forms.

Before a machine learning algorithm can be used to model a particularproblem, the algorithm is trained using a training data set. Training aneural network involves selecting a network topology, using a set oftraining data representing a problem being modeled by the network, andadjusting the weights until the network model performs with a minimalerror for all instances of the training data set. For example, during asupervised learning training process for a neural network, the outputproduced by the network in response to the input representing aninstance in a training data set is compared to the “correct” labeledoutput for that instance, an error signal representing the differencebetween the output and the labeled output is calculated, and the weightsassociated with the connections are adjusted to minimize that error asthe error signal is backward propagated through the layers of thenetwork. The network is considered “trained” when the errors for each ofthe outputs generated from the instances of the training data set areminimized.

The accuracy of a machine learning algorithm can be affectedsignificantly by the quality of the data set used to train thealgorithm. The training process can be computationally intensive and mayrequire a significant amount of time on a conventional general-purposeprocessor. Accordingly, parallel processing hardware is used to trainmany types of machine learning algorithms. This is particularly usefulfor optimizing the training of neural networks, as the computationsperformed in adjusting the coefficients in neural networks lendthemselves naturally to parallel implementations. Specifically, manymachine learning algorithms and software applications have been adaptedto make use of the parallel processing hardware within general-purposegraphics processing devices.

FIG. 6 is a generalized diagram of a machine learning software stack600. A machine learning application 602 can be configured to train aneural network using a training dataset or to use a trained deep neuralnetwork to implement machine intelligence. The machine learningapplication 602 can include training and inference functionality for aneural network and/or specialized software that can be used to train aneural network before deployment. The machine learning application 602can implement any type of machine intelligence including but not limitedto image recognition, mapping and localization, autonomous navigation,speech synthesis, medical imaging, or language translation.

Hardware acceleration for the machine learning application 602 can beenabled via a machine learning framework 604. The machine learningframework 604 can provide a library of machine learning primitives.Machine learning primitives are basic operations that are commonlyperformed by machine learning algorithms. Without the machine learningframework 604, developers of machine learning algorithms would berequired to create and optimize the main computational logic associatedwith the machine learning algorithm, then re-optimize the computationallogic as new parallel processors are developed. Instead, the machinelearning application can be configured to perform the necessarycomputations using the primitives provided by the machine learningframework 604. Exemplary primitives include tensor convolutions,activation functions, and pooling, which are computational operationsthat are performed while training a convolutional neural network (CNN).The machine learning framework 604 can also provide primitives toimplement basic linear algebra subprograms performed by manymachine-learning algorithms, such as matrix and vector operations.

The machine learning framework 604 can process input data received fromthe machine learning application 602 and generate the appropriate inputto a compute framework 606. The compute framework 606 can abstract theunderlying instructions provided to the GPGPU driver 608 to enable themachine learning framework 604 to take advantage of hardwareacceleration via the GPGPU hardware 610 without requiring the machinelearning framework 604 to have intimate knowledge of the architecture ofthe GPGPU hardware 610. Additionally, the compute framework 606 canenable hardware acceleration for the machine learning framework 604across a variety of types and generations of the GPGPU hardware 610.

GPGPU Machine Learning Acceleration

FIG. 7 illustrates a highly-parallel general-purpose graphics processingunit 700 according to an exemplary embodiment. In one embodiment, thegeneral-purpose processing unit (GPGPU) 700 can be configured to beparticularly efficient in processing the type of computational workloadsassociated with training deep neural networks. Additionally, the GPGPU700 can be linked directly to other instances of the GPGPU to create amulti-GPU cluster to improve training speed for particularly deep neuralnetworks.

The GPGPU 700 includes a host interface 702 to enable a connection witha host processor. In one embodiment, the host interface 702 is a PCIExpress interface. However, the host interface can also be a vendorspecific communications interface or communications fabric. The GPGPU700 receives commands from the host processor and uses a globalscheduler 704 to distribute execution threads associated with thosecommands to a set of compute clusters 706A-H. The compute clusters706A-H share a cache memory 708. The cache memory 708 can serve as ahigher-level cache for cache memories within the compute clusters706A-H.

The GPGPU 700 includes memory 714A-B coupled with the compute clusters706A-H via a set of memory controllers 712A-B. In various embodiments,the memory 714A-B can include various types of memory devices includingdynamic random access memory (DRAM) or graphics random access memory,such as synchronous graphics random access memory (SGRAM), includinggraphics double data rate (GDDR) memory. In one embodiment, the memoryunits 224A-N may also include 3D stacked memory, including but notlimited to high bandwidth memory (HBM).

In one embodiment, each compute cluster 706A-H includes a set ofgraphics multiprocessors, such as the graphics multiprocessor of FIG.4A. The graphics multiprocessors of the compute cluster multiple typesof integer and floating point logic units that can perform computationaloperations at a range of precisions including suited for machinelearning computations. For example, and in one embodiment, at least asubset of the floating-point units in each of the compute clusters706A-H can be configured to perform 16-bit or 32-bit floating pointoperations, while a different subset of floating point units can beconfigured to perform 64-bit floating point operations.

Multiple instances of the GPGPU 700 can be configured to operate as acompute cluster. The communication mechanism used by the compute clusterfor synchronization and data exchange varies across embodiments. In oneembodiment, the multiple instances of the GPGPU 700 communicate over thehost interface 702. In one embodiment, the GPGPU 700 includes an I/O hub709 that couples the GPGPU 700 with a GPU link 710 that enables a directconnection to other instances of the GPGPU. In one embodiment, the GPUlink 710 is coupled to a dedicated GPU-to-GPU bridge that enablescommunication and synchronization between multiple instances of theGPGPU 700. In one embodiment, the GPU link 710 couples with a high speedinterconnect to transmit and receive data to other GPGPUs or parallelprocessors. In one embodiment, the multiple instances of the GPGPU 700are located in separate data processing systems and communicate via anetwork device that is accessible via the host interface 702. In oneembodiment, the GPU link 710 can be configured to enable a connection toa host processor in addition to or as an alternative to the hostinterface 702.

While the illustrated configuration of the GPGPU 700 can be configuredto train neural networks, one embodiment provides alternateconfiguration of the GPGPU 700 that can be configured for deploymentwithin a high performance or low power inferencing platform. In aninferencing configuration, the GPGPU 700 includes fewer of the computeclusters 706A-H relative to the training configuration. Additionally,memory technology associated with the memory 714A-B may differ betweeninferencing and training configurations. In one embodiment, theinferencing configuration of the GPGPU 700 can support inferencingspecific instructions. For example, an inferencing configuration canprovide support for one or more 8-bit integer dot product instructions,which are commonly used during inferencing operations for deployedneural networks.

FIG. 8 illustrates a multi-GPU computing system 800 according to anexemplary embodiment. The multi-GPU computing system 800 can include aprocessor 802 coupled to multiple GPGPUs 806A-D via a host interfaceswitch 804. The host interface switch 804, in one embodiment, is a PCIexpress switch device that couples the processor 802 to a PCI expressbus over which the processor 802 can communicate with the set of GPGPUs806A-D. Each of the multiple GPGPUs 806A-D can be an instance of theGPGPU 700 of FIG. 7 . The GPGPUs 806A-D can interconnect via a set ofhigh-speed point to point GPU to GPU links 816. The high-speed GPU toGPU links can connect to each of the GPGPUs 806A-D via a dedicated GPUlink, such as the GPU link 710 as in FIG. 7 . The P2P GPU links 816enable direct communication between each of the GPGPUs 806A-D withoutrequiring communication over the host interface bus to which theprocessor 802 is connected. With GPU-to-GPU traffic directed to the P2PGPU links, the host interface bus remains available for system memoryaccess or to communicate with other instances of the multi-GPU computingsystem 800, for example, via one or more network devices. While in theillustrated embodiment the GPGPUs 806A-D connect to the processor 802via the host interface switch 804, in one embodiment the processor 802includes direct support for the P2P GPU links 816 and can connectdirectly to the GPGPUs 806A-D.

Machine Learning Neural Network Implementations

The computing architecture provided by embodiments described herein canbe configured to perform the types of parallel processing that isparticularly suited for training and deploying neural networks formachine learning. A neural network can be generalized as a network offunctions having a graph relationship. As is well-known in the art,there are a variety of types of neural network implementations used inmachine learning. One exemplary type of neural network is thefeedforward network, as previously described.

A second exemplary type of neural network is the Convolutional NeuralNetwork (CNN). A CNN is a specialized feedforward neural network forprocessing data having a known, grid-like topology, such as image data.Accordingly, CNNs are commonly used for computer vision and imagerecognition applications, but they also may be used for other types ofpattern recognition such as speech and language processing. The nodes inthe CNN input layer are organized into a set of “filters” (featuredetectors inspired by the receptive fields found in the retina), and theoutput of each set of filters is propagated to nodes in successivelayers of the network. The computations for a CNN include applying theconvolution mathematical operation to each filter to produce the outputof that filter. Convolution is a specialized kind of mathematicaloperation performed by two functions to produce a third function that isa modified version of one of the two original functions. Inconvolutional network terminology, the first function to the convolutioncan be referred to as the input, while the second function can bereferred to as the convolution kernel. The output may be referred to asthe feature map. For example, the input to a convolution layer can be amultidimensional array of data that defines the various color componentsof an input image. The convolution kernel can be a multidimensionalarray of parameters, where the parameters are adapted by the trainingprocess for the neural network.

Recurrent neural networks (RNNs) are a family of feedforward neuralnetworks that include feedback connections between layers. RNNs enablemodeling of sequential data by sharing parameter data across differentparts of the neural network. The architecture for a RNN includes cycles.The cycles represent the influence of a present value of a variable onits own value at a future time, as at least a portion of the output datafrom the RNN is used as feedback for processing subsequent input in asequence. This feature makes RNNs particularly useful for languageprocessing due to the variable nature in which language data can becomposed.

The figures described below present exemplary feedforward, CNN, and RNNnetworks, as well as describe a general process for respectivelytraining and deploying each of those types of networks. It will beunderstood that these descriptions are exemplary and non-limiting as toany specific embodiment described herein and the concepts illustratedcan be applied generally to deep neural networks and machine learningtechniques in general.

The exemplary neural networks described above can be used to performdeep learning. Deep learning is machine learning using deep neuralnetworks. The deep neural networks used in deep learning are artificialneural networks composed of multiple hidden layers, as opposed toshallow neural networks that include only a single hidden layer. Deeperneural networks are generally more computationally intensive to train.However, the additional hidden layers of the network enable multisteppattern recognition that results in reduced output error relative toshallow machine learning techniques.

Deep neural networks used in deep learning typically include a front-endnetwork to perform feature recognition coupled to a back-end networkwhich represents a mathematical model that can perform operations (e.g.,object classification, speech recognition, etc.) based on the featurerepresentation provided to the model. Deep learning enables machinelearning to be performed without requiring hand crafted featureengineering to be performed for the model. Instead, deep neural networkscan learn features based on statistical structure or correlation withinthe input data. The learned features can be provided to a mathematicalmodel that can map detected features to an output. The mathematicalmodel used by the network is generally specialized for the specific taskto be performed, and different models will be used to perform differenttask.

Once the neural network is structured, a learning model can be appliedto the network to train the network to perform specific tasks. Thelearning model describes how to adjust the weights within the model toreduce the output error of the network. Backpropagation of errors is acommon method used to train neural networks. An input vector ispresented to the network for processing. The output of the network iscompared to the desired output using a loss function and an error valueis calculated for each of the neurons in the output layer. The errorvalues are then propagated backwards until each neuron has an associatederror value which roughly represents its contribution to the originaloutput. The network can then learn from those errors using an algorithm,such as the stochastic gradient descent algorithm, to update the weightsof the of the neural network.

FIGS. 9A-B illustrate an exemplary convolutional neural network. FIG. 9Aillustrates various layers within a CNN. As shown in FIG. 9A, anexemplary CNN used to model image processing can receive input 902describing the red, green, and blue (RGB) components of an input image.The input 902 can be processed by multiple convolutional layers (e.g.,convolutional layer 904, convolutional layer 906). The output from themultiple convolutional layers may optionally be processed by a set offully connected layers 908. Neurons in a fully connected layer have fullconnections to all activations in the previous layer, as previouslydescribed for a feedforward network. The output from the fully connectedlayers 908 can be used to generate an output result from the network.The activations within the fully connected layers 908 can be computedusing matrix multiplication instead of convolution. Not all CNNimplementations make use of fully connected layers 906. For example, insome implementations, the convolutional layer 906 can generate outputfor the CNN.

The convolutional layers are sparsely connected, which differs fromtraditional neural network configuration found in the fully connectedlayers 908. Traditional neural network layers are fully connected, suchthat every output unit interacts with every input unit. However, theconvolutional layers are sparsely connected because the output of theconvolution of a field is input (instead of the respective state valueof each of the nodes in the field) to the nodes of the subsequent layer,as illustrated. The kernels associated with the convolutional layersperform convolution operations, the output of which is sent to the nextlayer. The dimensionality reduction performed within the convolutionallayers is one aspect that enables the CNN to scale to process largeimages.

FIG. 9B illustrates exemplary computation stages within a convolutionallayer of a CNN. Input to a convolutional layer 912 of a CNN can beprocessed in three stages of a convolutional layer 914. The three stagescan include a convolution stage 916, a detector stage 918, and a poolingstage 920. The convolution layer 914 can then output data to asuccessive convolutional layer. The final convolutional layer of thenetwork can generate output feature map data or provide input to a fullyconnected layer, for example, to generate a classification value for theinput to the CNN.

In the convolution stage 916, the convolutional layer 914 can performseveral convolutions in parallel to produce a set of linear activations.The convolution stage 916 can include an affine transformation, which isany transformation that can be specified as a linear transformation plusa translation. Affine transformations include rotations, translations,scaling, and combinations of these transformations. The convolutionstage computes the output of functions (e.g., neurons) that areconnected to specific regions in the input, which can be determined asthe local region associated with the neuron. The neurons compute a dotproduct between the weights of the neurons and the region in the localinput to which the neurons are connected. The output from theconvolution stage 916 defines a set of linear activations that areprocessed by successive stages of the convolutional layer 914.

The linear activations can be processed by a detector stage 918. In thedetector stage 918, each linear activation is processed by a non-linearactivation function. The non-linear activation function increases thenonlinear properties of the overall network without affecting thereceptive fields of the convolution layer. Several types of non-linearactivation functions may be used. One particular type is the rectifiedlinear unit (ReLU), which uses an activation function defined asƒ(x)=max(0, x), such that the activation is threshold at zero.

The pooling stage 920 uses a pooling function that replaces the outputof the convolutional layer 906 with a summary statistic of the nearbyoutputs. The pooling function can be used to introduce translationinvariance into the neural network, such that small translations to theinput do not change the pooled outputs. Invariance to local translationcan be useful in scenarios where the presence of a feature in the inputdata is more important than the precise location of the feature. Varioustypes of pooling functions can be used during the pooling stage 920,including max pooling, average pooling, and 12-norm pooling.Additionally, some CNN implementations do not include a pooling stage.Instead, such implementations substitute and additional convolutionstage having an increased stride relative to previous convolutionstages.

The output from the convolutional layer 914 can then be processed by thenext layer 922. The next layer 922 can be an additional convolutionallayer or one of the fully connected layers 908. For example, the firstconvolutional layer 904 of FIG. 9A can output to the secondconvolutional layer 906, while the second convolutional layer can outputto a first layer of the fully connected layers 908.

FIG. 10 illustrates an exemplary recurrent neural network 1000. In arecurrent neural network (RNN), the previous state of the networkinfluences the output of the current state of the network. RNNs can bebuilt in a variety of ways using a variety of functions. The use of RNNsgenerally revolves around using mathematical models to predict thefuture based on a prior sequence of inputs. For example, an RNN may beused to perform statistical language modeling to predict an upcomingword given a previous sequence of words. The illustrated RNN 1000 can bedescribed has having an input layer 1002 that receives an input vector,hidden layers 1004 to implement a recurrent function, a feedbackmechanism 1005 to enable a ‘memory’ of previous states, and an outputlayer 1006 to output a result. The RNN 1000 operates based ontime-steps. The state of the RNN at a given time step is influencedbased on the previous time step via the feedback mechanism 1005. For agiven time step, the state of the hidden layers 1004 is defined by theprevious state and the input at the current time step. An initial input(x₁) at a first time step can be processed by the hidden layer 1004. Asecond input (x₂) can be processed by the hidden layer 1004 using stateinformation that is determined during the processing of the initialinput (x₁). A given state can be computed as s_(t)=ƒ(Ux_(t)+Ws_(t-1)),where U and W are parameter matrices. The function ƒ is generally anonlinearity, such as the hyperbolic tangent function (Tanh) or avariant of the rectifier function ƒ(x)=max(0, x). However, the specificmathematical function used in the hidden layers 1004 can vary dependingon the specific implementation details of the RNN 1000.

In addition to the basic CNN and RNN networks described, variations onthose networks may be enabled. One example RNN variant is the long shortterm memory (LSTM) RNN. LSTM RNNs are capable of learning long-termdependencies that may be necessary for processing longer sequences oflanguage. A variant on the CNN is a convolutional deep belief network,which has a structure similar to a CNN and is trained in a mannersimilar to a deep belief network. A deep belief network (DBN) is agenerative neural network that is composed of multiple layers ofstochastic (random) variables. DBNs can be trained layer-by-layer usinggreedy unsupervised learning. The learned weights of the DBN can then beused to provide pre-train neural networks by determining an optimalinitial set of weights for the neural network.

FIG. 11 illustrates an exemplary training and deployment of a deepneural network. Once a given network has been structured for a task theneural network is trained using a training dataset 1102. Varioustraining frameworks 1104 have been developed to enable hardwareacceleration of the training process. For example, the machine learningframework 604 of FIG. 6 may be configured as a training framework 604.The training framework 604 can hook into an untrained neural network1106 and enable the untrained neural net to be trained using theparallel processing resources described herein to generate a trainedneural net 1108.

To start the training process the initial weights may be chosen randomlyor by pre-training using a deep belief network. The training cycle thenbe performed in either a supervised or unsupervised manner.

Supervised learning is a learning method in which training is performedas a mediated operation, such as when the training dataset 1102 includesinput paired with the desired output for the input, or where thetraining dataset includes input having known output and the output ofthe neural network is manually graded. The network processes the inputsand compares the resulting outputs against a set of expected or desiredoutputs. Errors are then propagated back through the system. Thetraining framework 1104 can adjust to adjust the weights that controlthe untrained neural network 1106. The training framework 1104 canprovide tools to monitor how well the untrained neural network 1106 isconverging towards a model suitable to generating correct answers basedon known input data. The training process occurs repeatedly as theweights of the network are adjusted to refine the output generated bythe neural network. The training process can continue until the neuralnetwork reaches a statistically desired accuracy associated with atrained neural net 1108. The trained neural network 1108 can then bedeployed to implement any number of machine learning operations.

Unsupervised learning is a learning method in which the network attemptsto train itself using unlabeled data. Thus, for unsupervised learningthe training dataset 1102 will include input data without any associatedoutput data. The untrained neural network 1106 can learn groupingswithin the unlabeled input and can determine how individual inputs arerelated to the overall dataset. Unsupervised training can be used togenerate a self-organizing map, which is a type of trained neuralnetwork 1108 capable of performing operations useful in reducing thedimensionality of data. Unsupervised training can also be used toperform anomaly detection, which allows the identification of datapoints in an input dataset that deviate from the normal patterns of thedata.

Variations on supervised and unsupervised training may also be employed.Semi-supervised learning is a technique in which in the training dataset1102 includes a mix of labeled and unlabeled data of the samedistribution. Incremental learning is a variant of supervised learningin which input data is continuously used to further train the model.Incremental learning enables the trained neural network 1108 to adapt tothe new data 1112 without forgetting the knowledge instilled within thenetwork during initial training.

Whether supervised or unsupervised, the training process forparticularly deep neural networks may be too computationally intensivefor a single compute node. Instead of using a single compute node, adistributed network of computational nodes can be used to accelerate thetraining process.

FIG. 12 is an exemplary block diagram illustrating distributed learning,Distributed learning is a training model that uses multiple distributedcomputing nodes to perform supervised or unsupervised training of aneural network. The distributed computational nodes can each include oneor more host processors and one or more of the general-purposeprocessing nodes, such as the highly-parallel general-purpose graphicsprocessing unit 700 as in FIG. 7 . As illustrated, distributed learningcan be performed model parallelism 1202, data parallelism 1204, or acombination of model and data parallelism 1204.

In model parallelism 1202, different computational nodes in adistributed system can perform training computations for different partsof a single network. For example, each layer of a neural network can betrained by a different processing node of the distributed system. Thebenefits of model parallelism include the ability to scale toparticularly large models. Splitting the computations associated withdifferent layers of the neural network enables the training of verylarge neural networks in which the weights of all layers would not fitinto the memory of a single computational node. In some instances, modelparallelism can be particularly useful in performing unsupervisedtraining of large neural networks.

In data parallelism 1204, the different nodes of the distributed networkhave a complete instance of the model and each node receives a differentportion of the data. The results from the different nodes are thencombined. While different approaches to data parallelism are possible,data parallel training approaches all require a technique of combiningresults and synchronizing the model parameters between each node.Exemplary approaches to combining data include parameter averaging andupdate based data parallelism. Parameter averaging trains each node on asubset of the training data and sets the global parameters (e.g.,weights, biases) to the average of the parameters from each node.Parameter averaging uses a central parameter server that maintains theparameter data. Update based data parallelism is similar to parameteraveraging except that instead of transferring parameters from the nodesto the parameter server, the updates to the model are transferred.Additionally, update based data parallelism can be performed in adecentralized manner, where the updates are compressed and transferredbetween nodes.

Combined model and data parallelism 1206 can be implemented, forexample, in a distributed system in which each computational nodeincludes multiple GPUs. Each node can have a complete instance of themodel with separate GPUs within each node are used to train differentportions of the model.

Distributed training has increased overhead relative to training on asingle machine. However, the parallel processors and GPGPUs describedherein can each implement various techniques to reduce the overhead ofdistributed training, including techniques to enable high bandwidthGPU-to-GPU data transfer and accelerated remote data synchronization.

Exemplary Machine Learning Applications

Machine learning can be applied to solve a variety of technologicalproblems, including but not limited to computer vision, autonomousdriving and navigation, speech recognition, and language processing.Computer vision has traditionally been one of the most active researchareas for machine learning applications. Applications of computer visionrange from reproducing human visual abilities, such as recognizingfaces, to creating new categories of visual abilities. For example,computer vision applications can be configured to recognize sound wavesfrom the vibrations induced in objects visible in a video. Parallelprocessor accelerated machine learning enables computer visionapplications to be trained using significantly larger training datasetthan previously feasible and enables inferencing systems to be deployedusing low power parallel processors.

Parallel processor accelerated machine learning has autonomous drivingapplications including lane and road sign recognition, obstacleavoidance, navigation, and driving control. Accelerated machine learningtechniques can be used to train driving models based on datasets thatdefine the appropriate responses to specific training input. Theparallel processors described herein can enable rapid training of theincreasingly complex neural networks used for autonomous drivingsolutions and enables the deployment of low power inferencing processorsin a mobile platform suitable for integration into autonomous vehicles.

Parallel processor accelerated deep neural networks have enabled machinelearning approaches to automatic speech recognition (ASR). ASR includesthe creation of a function that computes the most probable linguisticsequence given an input acoustic sequence. Accelerated machine learningusing deep neural networks have enabled the replacement of the hiddenMarkov models (HMMs) and Gaussian mixture models (GMMs) previously usedfor ASR.

Parallel processor accelerated machine learning can also be used toaccelerate natural language processing. Automatic learning procedurescan make use of statistical inference algorithms to produce models thatare robust to erroneous or unfamiliar input. Exemplary natural languageprocessor applications include automatic machine translation betweenhuman languages.

The parallel processing platforms used for machine learning can bedivided into training platforms and deployment platforms. Trainingplatforms are generally highly parallel and include optimizations toaccelerate multi-GPU single node training and multi-node, multi-GPUtraining. Exemplary parallel processors suited for training include thehighly-parallel general-purpose graphics processing unit 700 of FIG. 7and the multi-GPU computing system 800 of FIG. 8 . On the contrary,deployed machine learning platforms generally include lower powerparallel processors suitable for use in products such as cameras,autonomous robots, and autonomous vehicles.

FIG. 13 illustrates an exemplary inferencing system on a chip (SOC) 1300suitable for performing inferencing using a trained model. The SOC 1300can integrate processing components including a media processor 1302, avision processor 1304, a GPGPU 1306 and a multi-core processor 1308. TheSOC 1300 can additionally include on-chip memory 1305 that can enable ashared on-chip data pool that is accessible by each of the processingcomponents. The processing components can be optimized for low poweroperation to enable deployment to a variety of machine learningplatforms, including autonomous vehicles and autonomous robots. Forexample, one implementation of the SOC 1300 can be used as a portion ofthe main control system for an autonomous vehicle. Where the SOC 1300 isconfigured for use in autonomous vehicles the SOC is designed andconfigured for compliance with the relevant functional safety standardsof the deployment jurisdiction.

During operation, the media processor 1302 and vision processor 1304 canwork in concert to accelerate computer vision operations. The mediaprocessor 1302 can enable low latency decode of multiple high-resolution(e.g., 4K, 8K) video streams. The decoded video streams can be writtento a buffer in the on-chip-memory 1305. The vision processor 1304 canthen parse the decoded video and perform preliminary processingoperations on the frames of the decoded video in preparation ofprocessing the frames using a trained image recognition model. Forexample, the vision processor 1304 can accelerate convolution operationsfor a CNN that is used to perform image recognition on thehigh-resolution video data, while back end model computations areperformed by the GPGPU 1306.

The multi-core processor 1308 can include control logic to assist withsequencing and synchronization of data transfers and shared memoryoperations performed by the media processor 1302 and the visionprocessor 1304. The multi-core processor 1308 can also function as anapplication processor to execute software applications that can make useof the inferencing compute capability of the GPGPU 1306. For example, atleast a portion of the navigation and driving logic can be implementedin software executing on the multi-core processor 1308. Such softwarecan directly issue computational workloads to the GPGPU 1306 or thecomputational workloads can be issued to the multi-core processor 1308,which can offload at least a portion of those operations to the GPGPU1306.

The GPGPU 1306 can include compute clusters such as a low powerconfiguration of the compute clusters 706A-706H within thehighly-parallel general-purpose graphics processing unit 700. Thecompute clusters within the GPGPU 1306 can support instruction that arespecifically optimized to perform inferencing computations on a trainedneural network. For example, the GPGPU 1306 can support instructions toperform low precision computations such as 8-bit and 4-bit integervector operations.

Improved Boosting of Deep Neural Networks

FIG. 14 is an exemplary block diagram of a basic boosting architecture1400 having a boosted deep neural network system (DNN) system 1404 toreceive training data 1402 for learning and training a DNN. Trainingdata 1402 can include any number of samples including samples of imagesor related data and information. In some embodiments, boosted DNN system1404 can include or be implemented by or with the systems and processorsdisclosed and described in FIGS. 1-8 and 19-32 . In other embodiments,boosted DNN system 1404 can be implemented using hardware accelerationas described in FIGS. 6 and 7 . Training data 1402 can include imagesamples in any number of formats including Red Green Blue (RGB) formathaving R, G, and B channel values. Other examples include image samplesin Color Space Pixel (YUV) having luminance, color, and chrominancechannel values.

In exemplary embodiments, boosted DNN system 1404 implements boostingtechniques to train a DNN (e.g., a deep Convolutional Neural Network(CNN)) according to the description regarding FIGS. 15A-15B in which aDNN is comprised of shallow CNN networks that are boosted and trained.In examples disclosed in FIGS. 15A-15B, the loss of each shallow CNNnetwork is used to train the a deep DNN. In this way, training shallowCNN networks can provide a more effective and efficient training processfor a deep DNN.

In other exemplary embodiments, boosted DNN system 1404 implementsboosting techniques to train a DNN according to the descriptionregarding FIGS. 16-18 in which a DNN is comprised of weak CNN networksrequiring a portion of a training sample, and some of these weak CNNnetworks are combined and trained to form a strong CNN network. In thisway, a more efficient training process can be achieved by using asmaller amount of training data for the weak CNN networks.

Boosting of Shallow CNN Networks for Deep Learning

FIG. 15A illustrates an exemplary process 1500 of boosting a deep CNN1502 comprised of shallow CNN networks 1503 (e.g., Conv-1 1503-1 throughConv-k 1503-k) using the loss (e.g., loss 1506-1 through loss 1506-k) ofeach shallow CNN network in the training stage 1505. Deep CNN 1502 canbe any type of deep neural network as described herein with any numberof layers. In this example, deep CNN 1502 can include shallow CNNnetworks 1503 in which Conv-1 1503-1 through Conv-k 1503-k are subsetCNN networks within deep CNN 1502. In some embodiments, shallow CNNnetworks 1502 can be a fraction of deep CNN 1502. As such, each shallowCNN network Cov-1 1503-1 through Conv-k 1503-k can process a portion ora subset of a sample image (e.g., training data 1402 of FIG. 14 ) havingdifferent and varying data distributions. In these examples, K is aninteger.

At the training stage 1505, each shallow CNN network 1503-1 through1503-k is trained by a boosting algorithm such that the loss of eachshallow CNN network is used by a subsequent shallow CNN to adjustclassifier parameters accordingly based on the loss. In exemplaryembodiments, any type of machine learning boosting algorithm can be usedsuch as Adaptive Boosting or AdaBoost. As a result, training stage 1505can take advantage of statistics from training data based on the lossesfor each shallow CNN network (1503-1 through 1503-k) using a machinelearning technique. In this way, training stage 1505 can train fewer CNNnetworks with different distribution data. Thus, in exemplaryembodiments, the previous shallow CNN network is a guide to the next onefor learning in which training samples can be reweighted at the layersof each shallow CNN network. For example, as shown, in FIG. 15A, theloss of each shallow CNN network is used by the next shallow CNNnetwork—i.e., the loss of Conv-1 1503-1 is used by Conv-2 1503-2 and theloss of Conv-2 1503-2 is used by the next shallow CNN network untilConv-k 1503-k).

Additionally, at the training stage 1505, the output of each shallow CNNnetwork (Conv-1 1503-1 through Conv-k 1503-k) is input to inference 1508that can make predictions of the output of each shallow CNN network inshallow CNN networks 1503. In one embodiment, the layers of the kshallow CNN networks (1503-1 through 1503-k) can address differentprobability distributions for varying samples. Thus, based on the losses1506-1 through 1506-k and inference 1508, training stage 1505 can traindeep CNN 1502 using less sampling and training data concerning shallowCNN networks 1503 which are a subset of deep CNN 1502.

FIG. 15B is a flow diagram of an operation 1550 for boosting a deep CNN1502 comprised of shallow CNN networks 1503 and to train the deep CNN1502 using the loss (1506-1 through 1506-k) of each shallow CNN networkaccording to the example of FIG. 15A. At operation 1552, samples areprocessed by the shallow CNN networks 1503. For example, raw trainingdata from a sample is processed by Conv-1 1503-1 by applying equalweights for each data to learn a model with Conv-1 1503-1 (e.g., thefirst classifier).

At operation 1554, the loss for the shallow CNN networks 1503 isdetermined. For example, the loss for Conv-1 1503-1 can be determined bycomparing results (classifications) of training samples with a correctresult to determine types of classification errors.

At operation 1556, the training data is reweighted based on the loss ofthe shallow CNN networks 1503. For example, the training data for Conv-1can be re-weighted based on the loss 1506-1 for Conv-1 1503-1. If thereis a large classification error, the training data for that error can beprovided a larger weight for the next shallow CNN network—i.e., Conv-11503-2. And vice versa, if the classification error is smaller, thetraining data for the error can be provided a smaller weight for thenext shallow CNN network. As such, Conv-2 1503-2 can be trained toclassify data that caused a large error, e.g., by Conv-1 1503-1, withmore accuracy. The operation for 1550 can be repeated for each of theshallow CNN networks Conv-1 1503-1 through Conv-k 1503-k until all theshallow CNN networks 1503 are trained accordingly.

In these exemplary embodiments, k can be designated to meet highaccuracy requirement for the training data. As a result, each subsequentshallow CNN network from Conv-1 1503-1 to Conv-k 1503-k can have adecreasing classification error associated with it. Here, a boostingalgorithm can be used ensuring high performance for each shallow CNNnetwork Conv-1 1503-1 through Conv-k 1503-k that leverages both deeplearning and machine learning boosting techniques.

Boosting Weak CNN Networks for Deep Learning

FIG. 16 illustrates an exemplary boosting process 1600 for testing anensemble of deep CNNs. In this example, train samples 1602 can includetraining data for samples of any type of image. For example, for a giventraining sample from train samples 1602, subsets of training data of thesample (e.g., sub-set 1 1603-1 through sub-set k 1603-k) are designatedfor respective CNN networks or weak networks 1 (1605-1) though k(1605-k). Thus, the weak networks 1 (1605-1) through k (1605-k) onlyrequire processing a portion of the data for the training sample. Inthese examples, K is an integer.

The output or classification of each weak network 1 (1605-1) through k(1605-k) is evaluated (evaluate 1 1606-1 through evaluate k 1606-k)which is used to adjust classification parameters for a subsequentweak-network. For example, a classification error for the output(evaluate 1 1606-1) of weak network 1 1605-1 can be used to adjust (orboost) classification properties and parameters for a subsequent weaknetwork and so on up to weak network k 1605-k. In an exemplaryembodiment, any type of machine learning boosting algorithm can be usedsuch as AdaBoost to adjust classification properties and parameters(e.g., weights) for the weak networks 1 (1605-1) through k (1605-k). Theclassification of each of the weak networks 1 though k can be combinedin forming a stronger classification, which uses less training sampledata and can provide with high classification accuracy.

FIG. 17 is a block diagram according to exemplary embodiment of aboosting architecture 1700 to train a deep CNN such as a deep CNNcomprised of weak networks 1 (1605-1) through k (1605-k) shown in FIG.16 . In this example, a boosting algorithm such as AdaBoost can be usedto train weak networks 1 (1605-1) through k (1605-k). In one embodiment,the weak networks start training with initialized weights. Such weightsare parameters used to detect features in portions of an image at nodesof the CNN. Training data 1702 can include any number of trainingimages, which can be selected by image selector 1708 for training theweak networks 1 (1605-1) through k (1605-k). Normalizer 1706 cannormalize weights of the images during training of the weak networks 1(1605-1) through k (1605-k).

In one embodiment, image selector 1708 selects a subset of trainingimages from training data 1702 based on normalized weights by normalizer1706. Pixel selector 1710 can select certain blocks or portions of atraining image that are examined by a trainer 1712 and in whichclassification errors can be determined for weak networks 1714 (e.g.,weak networks 1 (1605-1) through k (1605-k) in FIG. 16 ). The trainer1712 can implement any type of boosting algorithm such as AdaBoost andwith weight updater 1716 and update weights through weightinitialization 1704 and train another weak network.

FIGS. 18A-18B are flow diagrams of operations to boost a deep CNNcomprised of weak networks according to exemplary embodiments. Referringto FIG. 18A, at operation 1805, weights are initialized for the weaknetworks. For example, weight initialization 1704 can initialize weightsfor selecting images before training of weak networks 1 (1605-1) throughk (1605-k). At operation 1810, each I^(th) weak network is boosted basedon the processed training images. Referring to FIG. 18B, operation 1810includes operations 1811 through 1814 which are performed for each weaknetwork up to k weak networks. For example, for each weak network 1(1605-1) through k (1605-k), iterative operations 1811 through 1814 areperformed for operation 1810.

At operation 1811, weights are normalized. For example, for I=2, weaknetwork 2 can have its weights normalized based on classification errordetermined by the output of weak network 1. At operation 1812, for theI^(th) weak network, a subset of training images is selected based onthe normalized weights. At operation 1813, the I^(th) weak network istrained using selected subsets of training images. In one example,90-100% of the pixels or selected pixels in the training images of theselected subset can be used to train the weak networks. This process caninclude determining a classification error based on the weights used. Atoperation 1814, depending on the classification errors determined forthe I^(th) weak network, weights are updated that are used for the nextweak network, e.g., if I=2, the updated weights can be used for weaknetwork 3. For example, if the classification error was large, theweights can be adjusted accordingly (i.e., increase) to address for thelarge classification error and, vice versa, if the error is small applya small adjustment of the weights. Such an adjustment can be implementedby any type of boosting algorithm such as AdaBoost.

Referring back to FIG. 18A, after operation 1810, the weak networks,e.g., weak network 1 (1605-1) through k (1605-k), are combined as asingle strong CNN ensemble or classifier. In one example, weak network 1(1605-1) through k (1605-k) are combined as a linear combination of kclassifiers. As such, less training data is needed according tooperation 1800 referring to FIGS. 18A-18B such that convergence is fastof the weak networks into a strong network.

Graphics System Overview

FIG. 19 is a block diagram of a processing system 1900 according to anexemplary embodiment. In various embodiments, the system 1900 includesone or more processors 1902 and one or more graphics processors 1908,and may be a single processor desktop system, a multiprocessorworkstation system, or a server system having a large number ofprocessors 1902 or processor cores 1907. In one embodiment, the system1900 is a processing platform incorporated within a system-on-a-chip(SoC) integrated circuit for use in mobile, handheld, or embeddeddevices.

An embodiment of system 1900 can include, or be incorporated within aserver-based gaming platform, a game console, including a game and mediaconsole, a mobile gaming console, a handheld game console, or an onlinegame console. In some embodiments system 1900 is a mobile phone, smartphone, tablet computing device or mobile Internet device. Dataprocessing system 1900 can also include, couple with, or be integratedwithin a wearable device, such as a smart watch wearable device, smarteyewear device, augmented reality device, or virtual reality device. Insome embodiments, data processing system 1900 is a television or set topbox device having one or more processors 1902 and a graphical interfacegenerated by one or more graphics processors 1908.

In some embodiments, the one or more processors 1902 each include one ormore processor cores 1907 to process instructions which, when executed,perform operations for system and user software. In some embodiments,each of the one or more processor cores 1907 is configured to process aspecific instruction set 1909. In some embodiments, instruction set 1909may facilitate Complex Instruction Set Computing (CISC), ReducedInstruction Set Computing (RISC), or computing via a Very Longinstruction Word (VLIW). Multiple processor cores 1907 may each processa different instruction set 1909, which may include instructions tofacilitate the emulation of other instruction sets. Processor core 1907may also include other processing devices, such a Digital SignalProcessor (DSP)).

In some embodiments, the processor 1902 includes cache memory 1904.Depending on the architecture, the processor 1902 can have a singleinternal cache or multiple levels of internal cache. In someembodiments, the cache memory is shared among various components of theprocessor 1902. In some embodiments, the processor 1902 also uses anexternal cache (e.g., a Level-3 (L3) cache or Last Level Cache (LLC))(not shown), which may be shared among processor cores 1907 using knowncache coherency techniques. A register file 1906 is additionallyincluded in processor 1902 which may include different types ofregisters for storing different types of data (e.g., integer registers,floating point registers, status registers, and an instruction pointerregister). Some registers may be general-purpose registers, while otherregisters may be specific to the design of the processor 1902.

In some embodiments, processor 1902 is coupled with a processor bus 1910to transmit communication signals such as address, data, or controlsignals between processor 1902 and other components in system 1900. Inone embodiment, the system 100 uses an exemplary ‘hub’ systemarchitecture, including a memory controller hub 1916 and an Input Output(I/O) controller hub 1930. A memory controller hub 1916 facilitatescommunication between a memory device and other components of system1900, while an I/O Controller Hub (ICH) 1930 provides connections to I/Odevices via a local I/O bus. In one embodiment, the logic of the memorycontroller hub 1916 is integrated within the processor.

Memory device 1920 can be a dynamic random access memory (DRAM) device,a static random access memory (SRAM) device, flash memory device,phase-change memory device, or some other memory device having suitableperformance to serve as process memory. In one embodiment, the memorydevice 1920 can operate as system memory for the system 1900, to storedata 1922 and instructions 1921 for use when the one or more processors1902 executes an application or process. Memory controller hub 1916 alsocouples with an optional external graphics processor 1912, which maycommunicate with the one or more graphics processors 1908 in processors1902 to perform graphics and media operations.

In some embodiments, ICH 1930 enables peripherals to connect to memorydevice 1920 and processor 1902 via a high-speed I/O bus. The I/Operipherals include, but are not limited to, an audio controller 1946, afirmware interface 1928, a wireless transceiver 1926 (e.g., Wi-Fi,Bluetooth), a data storage device 1924 (e.g., hard disk drive, flashmemory, etc.), and a legacy I/O controller 1940 for coupling legacy(e.g., Personal System 2 (PS/2)) devices to the system. One or moreUniversal Serial Bus (USB) controllers 1942 connect input devices, suchas keyboard and mouse 1944 combinations. A network controller 1934 mayalso couple with ICH 1930. In some embodiments, a high-performancenetwork controller (not shown) couples with processor bus 1910. It willbe appreciated that the system 1900 shown is exemplary and not limiting,as other types of data processing systems that are differentlyconfigured may also be used. For example, the I/O controller hub 1930may be integrated within the one or more processor 1902, or the memorycontroller hub 1916 and I/O controller hub 1930 may be integrated into adiscreet external graphics processor, such as the external graphicsprocessor 1912.

FIG. 20 is a block diagram of an exemplary embodiment of a processor2000 having one or more processor cores 2002A-2002N, an integratedmemory controller 2014, and an integrated graphics processor 2008. Thoseelements of FIG. 20 having the same reference numbers (or names) as theelements of any other figure herein can operate or function in anymanner similar to that described elsewhere herein, but are not limitedto such. Processor 2000 can include additional cores up to and includingadditional core 2002N represented by the dashed lined boxes. Each ofprocessor cores 2002A-2002N includes one or more internal cache units2004A-2004N. In some embodiments, each processor core also has access toone or more shared cached units 2006.

The internal cache units 2004A-2004N and shared cache units 2006represent a cache memory hierarchy within the processor 2000. The cachememory hierarchy may include at least one level of instruction and datacache within each processor core and one or more levels of sharedmid-level cache, such as a Level 2 (L2), Level 3 (L3), Level 4 (L4), orother levels of cache, where the highest level of cache before externalmemory is classified as the LLC. In some embodiments, cache coherencylogic maintains coherency between the various cache units 2006 and2004A-2004N.

In some embodiments, processor 2000 may also include a set of one ormore bus controller units 2016 and a system agent core 2010. The one ormore bus controller units 2016 manage a set of peripheral buses, such asone or more Peripheral Component Interconnect buses (e.g., PCI, PCIExpress). System agent core 2010 provides management functionality forthe various processor components. In some embodiments, system agent core2010 includes one or more integrated memory controllers 2014 to manageaccess to various external memory devices (not shown).

In some embodiments, one or more of the processor cores 2002A-2002Ninclude support for simultaneous multi-threading. In such embodiment,the system agent core 2010 includes components for coordinating andoperating cores 2002A-2002N during multi-threaded processing. Systemagent core 2010 may additionally include a power control unit (PCU),which includes logic and components to regulate the power state ofprocessor cores 2002A-2002N and graphics processor 2008.

In some embodiments, processor 2000 additionally includes graphicsprocessor 2008 to execute graphics processing operations. In someembodiments, the graphics processor 2008 couples with the set of sharedcache units 2006, and the system agent core 2010, including the one ormore integrated memory controllers 2014. In some embodiments, a displaycontroller 2011 is coupled with the graphics processor 2008 to drivegraphics processor output to one or more coupled displays. In someembodiments, display controller 2011 may be a separate module coupledwith the graphics processor via at least one interconnect, or may beintegrated within the graphics processor 2008 or system agent core 2010.

In some embodiments, a ring based interconnect unit 2012 is used tocouple the internal components of the processor 2000. However, analternative interconnect unit may be used, such as a point-to-pointinterconnect, a switched interconnect, or other techniques, includingtechniques well known in the art. In some embodiments, graphicsprocessor 2008 couples with the ring interconnect 2012 via an I/O link2013.

The exemplary I/O link 2013 represents at least one of multiplevarieties of I/O interconnects, including an on-package I/O interconnectwhich facilitates communication between various processor components anda high-performance embedded memory module 2018, such as an eDRAM module.In some embodiments, each of the processor cores 2002A-2002N andgraphics processor 2008 use embedded memory modules 2018 as a sharedLast Level Cache.

In some embodiments, processor cores 2002A-2002N are homogenous coresexecuting the same instruction set architecture. In another embodiment,processor cores 2002A-2002N are heterogeneous in terms of instructionset architecture (ISA), where one or more of processor cores 2002A-2002Nexecute a first instruction set, while at least one of the other coresexecutes a subset of the first instruction set or a differentinstruction set. In one embodiment processor cores 2002A-2002N areheterogeneous in terms of microarchitecture, where one or more coreshaving a relatively higher power consumption couple with one or morepower cores having a lower power consumption. Additionally, processor200 can be implemented on one or more chips or as an SoC integratedcircuit having the illustrated components, in addition to othercomponents.

FIG. 21 is a block diagram of a graphics processor 2100, which may be adiscrete graphics processing unit, or may be a graphics processorintegrated with a plurality of processing cores. In some embodiments,the graphics processor communicates via a memory mapped I/O interface toregisters on the graphics processor and with commands placed into theprocessor memory. In some embodiments, graphics processor 2100 includesa memory interface 2114 to access memory. Memory interface 2114 can bean interface to local memory, one or more internal caches, one or moreshared external caches, and/or to system memory.

In some embodiments, graphics processor 2100 also includes a displaycontroller 2102 to drive display output data to a display device 2120.Display controller 2102 includes hardware for one or more overlay planesfor the display and composition of multiple layers of video or userinterface elements. In some embodiments, graphics processor 2100includes a video codec engine 2106 to encode, decode, or transcode mediato, from, or between one or more media encoding formats, including, butnot limited to Moving Picture Experts Group (MPEG) formats such asMPEG-2, Advanced Video Coding (AVC) formats such as H.264/MPEG-4 AVC, aswell as the Society of Motion Picture & Television Engineers (SMPTE)421M/VC-1, and Joint Photographic Experts Group (JPEG) formats such asJPEG, and Motion JPEG (MJPEG) formats.

In some embodiments, graphics processor 2100 includes a block imagetransfer (BLIT) engine 2104 to perform two-dimensional (2D) rasterizeroperations including, for example, bit-boundary block transfers.However, in one embodiment, 2D graphics operations are performed usingone or more components of graphics processing engine (GPE) 2110. In someembodiments, GPE 2110 is a compute engine for performing graphicsoperations, including three-dimensional (3D) graphics operations andmedia operations.

In some embodiments, GPE 2110 includes a 3D pipeline 2112 for performing3D operations, such as rendering three-dimensional images and scenesusing processing functions that act upon 3D primitive shapes (e.g.,rectangle, triangle, etc.). The 3D pipeline 2112 includes programmableand fixed function elements that perform various tasks within theelement and/or spawn execution threads to a 3D/Media sub-system 2115.While 3D pipeline 2112 can be used to perform media operations, anembodiment of GPE 2110 also includes a media pipeline 2116 that isspecifically used to perform media operations, such as videopost-processing and image enhancement.

In some embodiments, media pipeline 2116 includes fixed function orprogrammable logic units to perform one or more specialized mediaoperations, such as video decode acceleration, video de-interlacing, andvideo encode acceleration in place of, or on behalf of video codecengine 2106. In some embodiments, media pipeline 2116 additionallyincludes a thread spawning unit to spawn threads for execution on3D/Media sub-system 2115. The spawned threads perform computations forthe media operations on one or more graphics execution units included in3D/Media sub-system 2115.

In some embodiments, 3D/Media subsystem 2115 includes logic forexecuting threads spawned by 3D pipeline 2112 and media pipeline 2116.In one embodiment, the pipelines send thread execution requests to3D/Media subsystem 2115, which includes thread dispatch logic forarbitrating and dispatching the various requests to available threadexecution resources. The execution resources include an array ofgraphics execution units to process the 3D and media threads. In someembodiments, 3D/Media subsystem 2115 includes one or more internalcaches for thread instructions and data. In some embodiments, thesubsystem also includes shared memory, including registers andaddressable memory, to share data between threads and to store outputdata.

Graphics Processing Engine

FIG. 22 is a block diagram of a graphics processing engine 2210 of agraphics processor in accordance with some embodiments. In oneembodiment, the graphics processing engine (GPE) 2210 is a version ofthe GPE 2110 shown in FIG. 21 . Elements of FIG. 22 having the samereference numbers (or names) as the elements of any other figure hereincan operate or function in any manner similar to that describedelsewhere herein, but are not limited to such. For example, the 3Dpipeline 2112 and media pipeline 2116 of FIG. 21 are illustrated. Themedia pipeline 2116 is optional in some embodiments of the GPE 2210 andmay not be explicitly included within the GPE 2210. For example, and inat least one embodiment, a separate media and/or image processor iscoupled to the GPE 2210.

In some embodiments, GPE 2210 couples with or includes a commandstreamer 2203, which provides a command stream to the 3D pipeline 2112and/or media pipelines 2116. In some embodiments, command streamer 2203is coupled with memory, which can be system memory, or one or more ofinternal cache memory and shared cache memory. In some embodiments,command streamer 2203 receives commands from the memory and sends thecommands to 3D pipeline 2112 and/or media pipeline 2116. The commandsare directives fetched from a ring buffer, which stores commands for the3D pipeline 2112 and media pipeline 2116. In one embodiment, the ringbuffer can additionally include batch command buffers storing batches ofmultiple commands. The commands for the 3D pipeline 2112 can alsoinclude references to data stored in memory, such as but not limited tovertex and geometry data for the 3D pipeline 2112 and/or image data andmemory objects for the media pipeline 2116. The 3D pipeline 2112 andmedia pipeline 2116 process the commands and data by performingoperations via logic within the respective pipelines or by dispatchingone or more execution threads to a graphics core array 2214.

In various embodiments, the 3D pipeline 2112 can execute one or moreshader programs, such as vertex shaders, geometry shaders, pixelshaders, fragment shaders, compute shaders, or other shader programs, byprocessing the instructions and dispatching execution threads to thegraphics core array 2214. The graphics core array 2214 provides aunified block of execution resources. Multi-purpose execution logic(e.g., execution units) within the graphic core array 2214 includessupport for various 3D API shader languages and can execute multiplesimultaneous execution threads associated with multiple shaders.

In some embodiments, the graphics core array 2214 also includesexecution logic to perform media functions, such as video and/or imageprocessing. In one embodiment, the execution units additionally includegeneral-purpose logic that is programmable to perform parallel generalpurpose computational operations, in addition to graphics processingoperations. The general-purpose logic can perform processing operationsin parallel or in conjunction with general purpose logic within theprocessor core(s) 1907 of FIG. 19 or core 2002A-2002N as in FIG. 20 .

Output data generated by threads executing on the graphics core array2214 can output data to memory in a unified return buffer (URB) 2218.The URB 2218 can store data for multiple threads. In some embodiments,the URB 2218 may be used to send data between different threadsexecuting on the graphics core array 2214. In some embodiments, the URB2218 may additionally be used for synchronization between threads on thegraphics core array and fixed function logic within the shared functionlogic 2220.

In some embodiments, graphics core array 2214 is scalable, such that thearray includes a variable number of graphics cores, each having avariable number of execution units based on the target power andperformance level of GPE 2210. In one embodiment, the executionresources are dynamically scalable, such that execution resources may beenabled or disabled as needed.

The graphics core array 2214 couples with shared function logic 2220that includes multiple resources that are shared between the graphicscores in the graphics core array. The shared functions within the sharedfunction logic 2220 are hardware logic units that provide specializedsupplemental functionality to the graphics core array 2214. In variousembodiments, shared function logic 2220 includes but is not limited tosampler 2221, math 2222, and inter-thread communication (ITC) 2223logic. Additionally, some embodiments implement one or more cache(s)2225 within the shared function logic 2220. A shared function isimplemented where the demand for a given specialized function isinsufficient for inclusion within the graphics core array 2214. Insteada single instantiation of that specialized function is implemented as astand-alone entity in the shared function logic 2220 and shared amongthe execution resources within the graphics core array 2214. The preciseset of functions that are shared between the graphics core array 2214and included within the graphics core array 2214 varies betweenembodiments.

FIG. 23 is a block diagram of another exemplary embodiment of a graphicsprocessor 500. Elements of FIG. 23 having the same reference numbers (ornames) as the elements of any other figure herein can operate orfunction in any manner similar to that described elsewhere herein, butare not limited to such.

In some embodiments, graphics processor 2300 includes a ringinterconnect 2302, a pipeline front-end 2305, a media engine 2337, andgraphics cores 2380A-2380N. In some embodiments, ring interconnect 2302couples the graphics processor to other processing units, includingother graphics processors or one or more general-purpose processorcores. In some embodiments, the graphics processor is one of manyprocessors integrated within a multi-core processing system.

In some embodiments, graphics processor 2300 receives batches ofcommands via ring interconnect 2302. The incoming commands areinterpreted by a command streamer 2303 in the pipeline front-end 2305.In some embodiments, graphics processor 2300 includes scalable executionlogic to perform 3D geometry processing and media processing via thegraphics core(s) 2380A-2380N. For 3D geometry processing commands,command streamer 2303 supplies commands to geometry pipeline 2336. Forat least some media processing commands, command streamer 2303 suppliesthe commands to a video front end 2334, which couples with a mediaengine 2337. In some embodiments, media engine 2337 includes a VideoQuality Engine (VQE) 2330 for video and image post-processing and amulti-format encode/decode (MFX) 2333 engine to providehardware-accelerated media data encode and decode. In some embodiments,geometry pipeline 2336 and media engine 2337 each generate executionthreads for the thread execution resources provided by at least onegraphics core 2380A.

In some embodiments, graphics processor 2300 includes scalable threadexecution resources featuring modular cores 2380A-2380N (sometimesreferred to as core slices), each having multiple sub-cores 2350A-2350N,2360A-2360N (sometimes referred to as core sub-slices). In someembodiments, graphics processor 2300 can have any number of graphicscores 2380A through 2380N. In some embodiments, graphics processor 2300includes a graphics core 2380A having at least a first sub-core 2350Aand a second sub-core 2360A. In other embodiments, the graphicsprocessor is a low power processor with a single sub-core (e.g., 2350A).In some embodiments, graphics processor 2300 includes multiple graphicscores 2380A-2380N, each including a set of first sub-cores 2350A-2350Nand a set of second sub-cores 2360A-2360N. Each sub-core in the set offirst sub-cores 2350A-2350N includes at least a first set of executionunits 2352A-2352N and media/texture samplers 2354A-2354N. Each sub-corein the set of second sub-cores 2360A-2360N includes at least a secondset of execution units 2362A-562N and samplers 2364A-2364N. In someembodiments, each sub-core 2350A-2350N, 2360A-2360N shares a set ofshared resources 2370A-2370N. In some embodiments, the shared resourcesinclude shared cache memory and pixel operation logic. Other sharedresources may also be included in the various embodiments of thegraphics processor.

Execution Units

FIG. 24 illustrates thread execution logic 2400 including an array ofprocessing elements employed in some exemplary embodiments of a GPE.Elements of FIG. 24 having the same reference numbers (or names) as theelements of any other figure herein can operate or function in anymanner similar to that described elsewhere herein, but are not limitedto such.

In some embodiments, thread execution logic 2400 includes a shaderprocessor 2402, a thread dispatcher 2404, instruction cache 2406, ascalable execution unit array including a plurality of execution units2408A-2408N, a sampler 2410, a data cache 2412, and a data port 2414. Inone embodiment, the scalable execution unit array can dynamically scaleby enabling or disabling one or more execution units (e.g., any ofexecution unit 2408A, 2408B, 2408C, 2408D, through 2408N-1 and 2408N)based on the computational requirements of a workload. In oneembodiment, the included components are interconnected via aninterconnect fabric that links to each of the components. In someembodiments, thread execution logic 2400 includes one or moreconnections to memory, such as system memory or cache memory, throughone or more of instruction cache 2406, data port 2414, sampler 2410, andexecution units 2408A-2408N. In some embodiments, each execution unit(e.g. 2408A) is a stand-alone programmable general purpose computationalunit that is capable of executing multiple simultaneous hardware threadswhile processing multiple data elements in parallel for each thread. Invarious embodiments, the array of execution units 2408A-2408N isscalable to include any number individual execution units.

In some embodiments, the execution units 2408A-2408N are primarily usedto execute shader programs. A shader processor 2402 can process thevarious shader programs and dispatch execution threads associated withthe shader programs via a thread dispatcher 2404. In one embodiment, thethread dispatcher includes logic to arbitrate thread initiation requestsfrom the graphics and media pipelines and instantiate the requestedthreads on one or more execution unit in the execution units2408A-2408N. For example, the geometry pipeline (e.g., 2336 of FIG. 23 )can dispatch vertex, tessellation, or geometry shaders to the threadexecution logic 2400 (FIG. 24 ) for processing. In some embodiments,thread dispatcher 2404 can also process runtime thread spawning requestsfrom the executing shader programs.

In some embodiments, the execution units 2408A-2408N support aninstruction set that includes native support for many standard 3Dgraphics shader instructions, such that shader programs from graphicslibraries (e.g., Direct 3D and OpenGL) are executed with a minimaltranslation. The execution units support vertex and geometry processing(e.g., vertex programs, geometry programs, vertex shaders), pixelprocessing (e.g., pixel shaders, fragment shaders) and general-purposeprocessing (e.g., compute and media shaders). Each of the executionunits 2408A-2408N is capable of multi-issue single instruction multipledata (SIMD) execution and multi-threaded operation enables an efficientexecution environment in the face of higher latency memory accesses.Each hardware thread within each execution unit has a dedicatedhigh-bandwidth register file and associated independent thread-state.Execution is multi-issue per clock to pipelines capable of integer,single and double precision floating point operations, SIMD branchcapability, logical operations, transcendental operations, and othermiscellaneous operations. While waiting for data from memory or one ofthe shared functions, dependency logic within the execution units2408A-2408N causes a waiting thread to sleep until the requested datahas been returned. While the waiting thread is sleeping, hardwareresources may be devoted to processing other threads. For example,during a delay associated with a vertex shader operation, an executionunit can perform operations for a pixel shader, fragment shader, oranother type of shader program, including a different vertex shader.

Each execution unit in execution units 2408A-2408N operates on arrays ofdata elements. The number of data elements is the “execution size,” orthe number of channels for the instruction. An execution channel is alogical unit of execution for data element access, masking, and flowcontrol within instructions. The number of channels may be independentof the number of physical Arithmetic Logic Units (ALUs) or FloatingPoint Units (FPUs) for a particular graphics processor. In someembodiments, execution units 608A-608N support integer andfloating-point data types.

The execution unit instruction set includes SIMD instructions. Thevarious data elements can be stored as a packed data type in a registerand the execution unit will process the various elements based on thedata size of the elements. For example, when operating on a 256-bit widevector, the 256 bits of the vector are stored in a register and theexecution unit operates on the vector as four separate 64-bit packeddata elements (Quad-Word (QW) size data elements), eight separate 32-bitpacked data elements (Double Word (DW) size data elements), sixteenseparate 16-bit packed data elements (Word (W) size data elements), orthirty-two separate 8-bit data elements (byte (B) size data elements).However, different vector widths and register sizes are possible.

One or more internal instruction caches (e.g., 2406) are included in thethread execution logic 2400 to cache thread instructions for theexecution units. In some embodiments, one or more data caches (e.g.,2412) are included to cache thread data during thread execution. In someembodiments, a sampler 2410 is included to provide texture sampling for3D operations and media sampling for media operations. In someembodiments, sampler 2410 includes specialized texture or media samplingfunctionality to process texture or media data during the samplingprocess before providing the sampled data to an execution unit.

During execution, the graphics and media pipelines send threadinitiation requests to thread execution logic 2400 via thread spawningand dispatch logic. Once a group of geometric objects has been processedand rasterized into pixel data, pixel processor logic (e.g., pixelshader logic, fragment shader logic, etc.) within the shader processor2402 is invoked to further compute output information and cause resultsto be written to output surfaces (e.g., color buffers, depth buffers,stencil buffers, etc.). In some embodiments, a pixel shader or fragmentshader calculates the values of the various vertex attributes that areto be interpolated across the rasterized object. In some embodiments,pixel processor logic within the shader processor 2402 then executes anapplication programming interface (API)-supplied pixel or fragmentshader program. To execute the shader program, the shader processor 2402dispatches threads to an execution unit 2408A) via thread dispatcher2404. In some embodiments, pixel shader 2402 uses texture sampling logicin the sampler 2410 to access texture data in texture maps stored inmemory. Arithmetic operations on the texture data and the input geometrydata compute pixel color data for each geometric fragment, or discardsone or more pixels from further processing.

In some embodiments, the data port 2414 provides a memory accessmechanism for the thread execution logic 2400 output processed data tomemory for processing on a graphics processor output pipeline. In someembodiments, the data port 2414 includes or couples to one or more cachememories (e.g., data cache 2412) to cache data for memory access via thedata port.

FIG. 25 is a block diagram illustrating a graphics processor instructionformats 2500 according to some embodiments. In one or more embodiment,the graphics processor execution units support an instruction set havinginstructions in multiple formats. The solid lined boxes illustrate thecomponents that are generally included in an execution unit instruction,while the dashed lines include components that are optional or that areonly included in a sub-set of the instructions. In some embodiments,instruction format 2500 described and illustrated aremacro-instructions, in that they are instructions supplied to theexecution unit, as opposed to micro-operations resulting frominstruction decode once the instruction is processed.

In some embodiments, the graphics processor execution units nativelysupport instructions in a 128-bit instruction format 2510. A 64-bitcompacted instruction format 2530 is available for some instructionsbased on the selected instruction, instruction options, and number ofoperands. The native 128-bit instruction format 2510 provides access toall instruction options, while some options and operations arerestricted in the 64-bit instruction format 2530. The nativeinstructions available in the 64-bit instruction format 2530 vary byembodiment. In some embodiments, the instruction is compacted in partusing a set of index values in an index field 2513. The execution unithardware references a set of compaction tables based on the index valuesand uses the compaction table outputs to reconstruct a nativeinstruction in the 128-bit instruction format 2510.

For each format, instruction opcode 2512 defines the operation that theexecution unit is to perform. The execution units execute eachinstruction in parallel across the multiple data elements of eachoperand. For example, in response to an add instruction the executionunit performs a simultaneous add operation across each color channelrepresenting a texture element or picture element. By default, theexecution unit performs each instruction across all data channels of theoperands. In some embodiments, instruction control field 2514 enablescontrol over certain execution options, such as channels selection(e.g., predication) and data channel order (e.g., swizzle). Forinstructions in the 128-bit instruction format 2510 an exec-size field2516 limits the number of data channels that will be executed inparallel. In some embodiments, exec-size field 2516 is not available foruse in the 64-bit compact instruction format 2530.

Some execution unit instructions have up to three operands including twosource operands, src0 2520, src1 2522, and one destination 2518. In someembodiments, the execution units support dual destination instructions,where one of the destinations is implied. Data manipulation instructionscan have a third source operand (e.g., SRC2 2524), where the instructionopcode 2512 determines the number of source operands. An instruction'slast source operand can be an immediate (e.g., hard-coded) value passedwith the instruction.

In some embodiments, the 128-bit instruction format 2510 includes anaccess/address mode field 2526 specifying, for example, whether directregister addressing mode or indirect register addressing mode is used.When direct register addressing mode is used, the register address ofone or more operands is directly provided by bits in the instruction.

In some embodiments, the 128-bit instruction format 2510 includes anaccess/address mode field 2526, which specifies an address mode and/oran access mode for the instruction. In one embodiment, the access modeis used to define a data access alignment for the instruction. Someembodiments support access modes including a 16-byte aligned access modeand a 1-byte aligned access mode, where the byte alignment of the accessmode determines the access alignment of the instruction operands. Forexample, when in a first mode, the instruction may use byte-alignedaddressing for source and destination operands and when in a secondmode, the instruction may use 16-byte-aligned addressing for all sourceand destination operands.

In one embodiment, the address mode portion of the access/address modefield 2526 determines whether the instruction is to use direct orindirect addressing. When direct register addressing mode is used bitsin the instruction directly provide the register address of one or moreoperands. When indirect register addressing mode is used, the registeraddress of one or more operands may be computed based on an addressregister value and an address immediate field in the instruction.

In some embodiments, instructions are grouped based on opcode 2512bit-fields to simplify Opcode decode 2540. For an 8-bit opcode, bits 4,5, and 6 allow the execution unit to determine the type of opcode. Theprecise opcode grouping shown is merely an example. In some embodiments,a move and logic opcode group 2542 includes data movement and logicinstructions (e.g., move (mov), compare (cmp)). In some embodiments,move and logic group 2542 shares the five most significant bits (MSB),where move (mov) instructions are in the form of 0000xxxxb and logicinstructions are in the form of 0001xxxxb. A flow control instructiongroup 2544 (e.g., call, jump (jmp)) includes instructions in the form of0010xxxxb (e.g., 0×20). A miscellaneous instruction group 2546 includesa mix of instructions, including synchronization instructions (e.g.,wait, send) in the form of 0011xxxxb (e.g., 0×30). A parallel mathinstruction group 2548 includes component-wise arithmetic instructions(e.g., add, multiply (mul)) in the form of 0100xxxxb (e.g., 0×40). Theparallel math group 2548 performs the arithmetic operations in parallelacross data channels. The vector math group 2550 includes arithmeticinstructions (e.g., dp4) in the form of 0101xxxxb (e.g., 0×50). Thevector math group performs arithmetic such as dot product calculationson vector operands.

Graphics Pipeline

FIG. 26 is a block diagram of another embodiment of a graphics processor2600. Elements of FIG. 26 having the same reference numbers (or names)as the elements of any other figure herein can operate or function inany manner similar to that described elsewhere herein, but are notlimited to such.

In some embodiments, graphics processor 2600 includes a graphicspipeline 2620, a media pipeline 2630, a display engine 2640, threadexecution logic 2650, and a render output pipeline 2670. In someembodiments, graphics processor 2600 is a graphics processor within amulti-core processing system that includes one or more general purposeprocessing cores. The graphics processor is controlled by registerwrites to one or more control registers (not shown) or via commandsissued to graphics processor 2600 via a ring interconnect 2602. In someembodiments, ring interconnect 2602 couples graphics processor 2600 toother processing components, such as other graphics processors orgeneral-purpose processors. Commands from ring interconnect 2602 areinterpreted by a command streamer 2603, which supplies instructions toindividual components of graphics pipeline 2620 or media pipeline 2630.

In some embodiments, command streamer 2603 directs the operation of avertex fetcher 2605 that reads vertex data from memory and executesvertex-processing commands provided by command streamer 2603. In someembodiments, vertex fetcher 2605 provides vertex data to a vertex shader2607, which performs coordinate space transformation and lightingoperations to each vertex. In some embodiments, vertex fetcher 2605 andvertex shader 2607 execute vertex-processing instructions by dispatchingexecution threads to execution units 2652A-2652B via a thread dispatcher2631.

In some embodiments, execution units 2652A-2652B are an array of vectorprocessors having an instruction set for performing graphics and mediaoperations. In some embodiments, execution units 2652A-2652B have anattached L1 cache 2651 that is specific for each array or shared betweenthe arrays. The cache can be configured as a data cache, an instructioncache, or a single cache that is partitioned to contain data andinstructions in different partitions.

In some embodiments, graphics pipeline 2620 includes tessellationcomponents to perform hardware-accelerated tessellation of 3D objects.In some embodiments, a programmable hull shader 2611 configures thetessellation operations. A programmable domain shader 2617 providesback-end evaluation of tessellation output. A tessellator 2613 operatesat the direction of hull shader 2611 and contains special purpose logicto generate a set of detailed geometric objects based on a coarsegeometric model that is provided as input to graphics pipeline 2620. Insome embodiments, if tessellation is not used, tessellation components(e.g., hull shader 2611, tessellator 2613, and domain shader 2617) canbe bypassed.

In some embodiments, complete geometric objects can be processed by ageometry shader 2619 via one or more threads dispatched to executionunits 2652A-2652B, or can proceed directly to the clipper 2629. In someembodiments, the geometry shader operates on entire geometric objects,rather than vertices or patches of vertices as in previous stages of thegraphics pipeline. If the tessellation is disabled the geometry shader2619 receives input from the vertex shader 2607. In some embodiments,geometry shader 2619 is programmable by a geometry shader program toperform geometry tessellation if the tessellation units are disabled.

Before rasterization, a clipper 2629 processes vertex data. The clipper2629 may be a fixed function clipper or a programmable clipper havingclipping and geometry shader functions. In some embodiments, arasterizer and depth test component 2673 in the render output pipeline2670 dispatches pixel shaders to convert the geometric objects intotheir per pixel representations. In some embodiments, pixel shader logicis included in thread execution logic 2650. In some embodiments, anapplication can bypass the rasterizer and depth test component 2673 andaccess un-rasterized vertex data via a stream out unit 2623.

The graphics processor 2600 has an interconnect bus, interconnectfabric, or some other interconnect mechanism that allows data andmessage passing amongst the major components of the processor. In someembodiments, execution units 2652A-2652B and associated cache(s) 2651,texture and media sampler 2654, and texture/sampler cache 2658interconnect via a data port 2656 to perform memory access andcommunicate with render output pipeline components of the processor. Insome embodiments, sampler 2654, caches 2651, 2658 and execution units2652A-2652B each have separate memory access paths.

In some embodiments, render output pipeline 2670 contains a rasterizerand depth test component 2673 that converts vertex-based objects into anassociated pixel-based representation. In some embodiments, therasterizer logic includes a windower/masker unit to perform fixedfunction triangle and line rasterization. An associated render cache2678 and depth cache 2679 are also available in some embodiments. Apixel operations component 2677 performs pixel-based operations on thedata, though in some instances, pixel operations associated with 2Doperations (e.g. bit block image transfers with blending) are performedby the 2D engine 2641, or substituted at display time by the displaycontroller 2643 using overlay display planes. In some embodiments, ashared L3 cache 2675 is available to all graphics components, allowingthe sharing of data without the use of main system memory.

In some embodiments, graphics processor media pipeline 2630 includes amedia engine 2637 and a video front end 2634. In some embodiments, videofront end 2634 receives pipeline commands from the command streamer2603. In some embodiments, media pipeline 2630 includes a separatecommand streamer. In some embodiments, video front-end 2634 processesmedia commands before sending the command to the media engine 2637. Insome embodiments, media engine 2637 includes thread spawningfunctionality to spawn threads for dispatch to thread execution logic2650 via thread dispatcher 2631.

In some embodiments, graphics processor 2600 includes a display engine2640. In some embodiments, display engine 2640 is external to processor2600 and couples with the graphics processor via the ring interconnect2602, or some other interconnect bus or fabric. In some embodiments,display engine 2640 includes a 2D engine 2641 and a display controller2643. In some embodiments, display engine 2640 contains special purposelogic capable of operating independently of the 3D pipeline. In someembodiments, display controller 2643 couples with a display device (notshown), which may be a system integrated display device, as in a laptopcomputer, or an external display device attached via a display deviceconnector.

In sonic embodiments, graphics pipeline 2620 and media pipeline 2630 areconfigurable to perform operations based on multiple graphics and mediaprogramming interfaces and are not specific to any one applicationprogramming interface (API). In some embodiments, driver software forthe graphics processor translates API calls that are specific to aparticular graphics or media library into commands that can be processedby the graphics processor. In some embodiments, support is provided forthe Open Graphics Library (OpenGL), Open Computing Language (OpenCL),and/or Vulkan graphics and compute API, all from the Khronos Group. Insome embodiments, support may also be provided for the Direct3D libraryfrom the Microsoft Corporation. In some embodiments, a combination ofthese libraries may be supported. Support may also be provided for theOpen Source Computer Vision Library (OpenCV). A future API with acompatible 3D pipeline would also be supported if a mapping can be madefrom the pipeline of the future API to the pipeline of the graphicsprocessor.

Graphics Pipeline Programming

FIG. 27A is a block diagram illustrating a graphics processor commandformat 2700 according to some embodiments. FIG. 27B is a block diagramillustrating a graphics processor command sequence 2710 according to anembodiment. The solid lined boxes in FIG. 27A illustrate the componentsthat are generally included in a graphics command while the dashed linesinclude components that are optional or that are only included in asub-set of the graphics commands. The exemplary graphics processorcommand format 2700 of FIG. 27A includes data fields to identify atarget client 2702 of the command, a command operation code (opcode)2704, and the relevant data 2706 for the command. A sub-opcode 2705 anda command size 2708 are also included in some commands.

In some embodiments, client 2702 specifies the client unit of thegraphics device that processes the command data. In some embodiments, agraphics processor command parser examines the client field of eachcommand to condition the further processing of the command and route thecommand data to the appropriate client unit. In some embodiments, thegraphics processor client units include a memory interface unit, arender unit, a 2D unit, a 3D unit, and a media unit. Each client unithas a corresponding processing pipeline that processes the commands.Once the command is received by the client unit, the client unit readsthe opcode 2704 and, if present, sub-opcode 2705 to determine theoperation to perform. The client unit performs the command usinginformation in data field 2706. For some commands an explicit commandsize 2708 is expected to specify the size of the command. In someembodiments, the command parser automatically determines the size of atleast some of the commands based on the command opcode. In someembodiments commands are aligned via multiples of a double word.

The flow diagram in FIG. 27B shows an exemplary graphics processorcommand sequence 2710. In some embodiments, software or firmware of adata processing system that features an embodiment of a graphicsprocessor uses a version of the command sequence shown to set up,execute, and terminate a set of graphics operations. A sample commandsequence is shown and described for purposes of example only asembodiments are not limited to these specific commands or to thiscommand sequence. Moreover, the commands may be issued as batch ofcommands in a command sequence, such that the graphics processor willprocess the sequence of commands in at least partially concurrence.

In some embodiments, the graphics processor command sequence 2710 maybegin with a pipeline flush command 2712 to cause any active graphicspipeline to complete the currently pending commands for the pipeline. Insome embodiments, the 3D pipeline 2722 and the media pipeline 2724 donot operate concurrently. The pipeline flush is performed to cause theactive graphics pipeline to complete any pending commands. In responseto a pipeline flush, the command parser for the graphics processor willpause command processing until the active drawing engines completepending operations and the relevant read caches are invalidated.Optionally, any data in the render cache that is marked ‘dirty’ can beflushed to memory. In some embodiments, pipeline flush command 2712 canbe used for pipeline synchronization or before placing the graphicsprocessor into a low power state.

In some embodiments, a pipeline select command 2713 is used when acommand sequence requires the graphics processor to explicitly switchbetween pipelines. In some embodiments, a pipeline select command 2713is required only once within an execution context before issuingpipeline commands unless the context is to issue commands for bothpipelines. In some embodiments, a pipeline flush command 2712 isrequired immediately before a pipeline switch via the pipeline selectcommand 2713.

In some embodiments, a pipeline control command 2714 configures agraphics pipeline for operation and is used to program the 3D pipeline2722 and the media pipeline 2724. In some embodiments, pipeline controlcommand 2714 configures the pipeline state for the active pipeline. Inone embodiment, the pipeline control command 2714 is used for pipelinesynchronization and to clear data from one or more cache memories withinthe active pipeline before processing a batch of commands.

In some embodiments, commands for the return buffer state 2716 are usedto configure a set of return buffers for the respective pipelines towrite data. Some pipeline operations require the allocation, selection,or configuration of one or more return buffers into which the operationswrite intermediate data during processing. In some embodiments, thegraphics processor also uses one or more return buffers to store outputdata and to perform cross thread communication. In some embodiments,configuring the return buffer state 2716 includes selecting the size andnumber of return buffers to use for a set of pipeline operations.

The remaining commands in the command sequence differ based on theactive pipeline for operations. Based on a pipeline determination 2720,the command sequence is tailored to the 3D pipeline 2722 beginning withthe 3D pipeline state 2730 or the media pipeline 2724 beginning at themedia pipeline state 2740.

The commands to configure the 3D pipeline state 2730 include 3D statesetting commands for vertex buffer state, vertex element state, constantcolor state, depth buffer state, and other state variables that are tobe configured before 3D primitive commands are processed. The values ofthese commands are determined at least in part based on the particular3D API in use. In some embodiments, 3D pipeline state 2730 commands arealso able to selectively disable or bypass certain pipeline elements ifthose elements will not be used.

In some embodiments, 3D primitive 2732 command is used to submit 3Dprimitives to be processed by the 3D pipeline. Commands and associatedparameters that are passed to the graphics processor via the 3Dprimitive 2732 command are forwarded to the vertex fetch function in thegraphics pipeline. The vertex fetch function uses the 3D primitive 2732command data to generate vertex data structures. The vertex datastructures are stored in one or more return buffers. In someembodiments, 3D primitive 2732 command is used to perform vertexoperations on 3D primitives via vertex shaders. To process vertexshaders, 3D pipeline 2722 dispatches shader execution threads tographics processor execution units.

In some embodiments, 3D pipeline 2722 is triggered via an execute 2734command or event. In some embodiments, a register write triggers commandexecution. In some embodiments execution is triggered via a ‘go’ or‘kick’ command in the command sequence. In one embodiment, commandexecution is triggered using a pipeline synchronization command to flushthe command sequence through the graphics pipeline. The 3D pipeline willperform geometry processing for the 3D primitives. Once operations arecomplete, the resulting geometric objects are rasterized and the pixelengine colors the resulting pixels. Additional commands to control pixelshading and pixel back end operations may also be included for thoseoperations.

In some embodiments, the graphics processor command sequence 2710follows the media pipeline 2724 path when performing media operations.In general, the specific use and manner of programming for the mediapipeline 2724 depends on the media or compute operations to beperformed. Specific media decode operations may be offloaded to themedia pipeline during media decode. In some embodiments, the mediapipeline can also be bypassed and media decode can be performed in wholeor in part using resources provided by one or more general purposeprocessing cores. In one embodiment, the media pipeline also includeselements for general-purpose graphics processor unit (GPGPU) operations,where the graphics processor is used to perform SIMD vector operationsusing computational shader programs that are not explicitly related tothe rendering of graphics primitives.

In some embodiments, media pipeline 2724 is configured in a similarmanner as the 3D pipeline 2722. A set of commands to configure the mediapipeline state 2740 are dispatched or placed into a command queue beforethe media object commands 2742. In some embodiments, commands for themedia pipeline state 2740 include data to configure the media pipelineelements that will be used to process the media objects. This includesdata to configure the video decode and video encode logic within themedia pipeline, such as encode or decode format. In some embodiments,commands for the media pipeline state 2740 also support the use of oneor more pointers to “indirect” state elements that contain a batch ofstate settings.

In some embodiments, media object commands 2742 supply pointers to mediaobjects for processing by the media pipeline. The media objects includememory buffers containing video data to be processed. In someembodiments, all media pipeline states must be valid before issuing amedia object command 2742. Once the pipeline state is configured andmedia object commands 2742 are queued, the media pipeline 2724 istriggered via an execute command 2744 or an equivalent execute event(e.g., register write). Output from media pipeline 2724 may then be postprocessed by operations provided by the 3D pipeline 2722 or the mediapipeline 2724. In some embodiments, GPGPU operations are configured andexecuted in a similar manner as media operations.

Graphics Software Architecture

FIG. 28 illustrates exemplary graphics software architecture for a dataprocessing system 2800 according to some embodiments. In someembodiments, software architecture includes a 3D graphics application2810, an operating system 2820, and at least one processor 2830. In someembodiments, processor 2830 includes a graphics processor 2832 and oneor more general-purpose processor core(s) 2834. The graphics application2810 and operating system 2820 each execute in the system memory 2850 ofthe data processing system.

In some embodiments, 3D graphics application 2810 contains one or moreshader programs including shader instructions 2812. The shader languageinstructions may be in a high-level shader language, such as the HighLevel Shader Language (HLSL) or the OpenGL Shader Language (GLSL). Theapplication also includes executable instructions 2814 in a machinelanguage suitable for execution by the general-purpose processor core2834. The application also includes graphics objects 2816 defined byvertex data.

In some embodiments, operating system 2820 is a Microsoft® Windows®operating system from the Microsoft Corporation, a proprietary UNIX-likeoperating system, or an open source UNIX-like operating system using avariant of the Linux kernel. The operating system 2820 can support agraphics API 2822 such as the Direct3D API, the OpenGL API, or theVulkan API. When the Direct3D API is in use, the operating system 2820uses a front-end shader compiler 2824 to compile any shader instructions2812 in HLSL into a lower-level shader language. The compilation may bea just-in-time (JIT) compilation or the application can perform shaderpre-compilation. In some embodiments, high-level shaders are compiledinto low-level shaders during the compilation of the 3D graphicsapplication 2810. In some embodiments, the shader instructions 2812 areprovided in an intermediate form, such as a version of the StandardPortable Intermediate Representation (SPIR) used by the Vulkan API.

In some embodiments, user mode graphics driver 2826 contains a back-endshader compiler 2827 to convert the shader instructions 2812 into ahardware specific representation. When the OpenGL API is in use, shaderinstructions 2812 in the GLSL high-level language are passed to a usermode graphics driver 2826 for compilation. In some embodiments, usermode graphics driver 2826 uses operating system kernel mode functions2828 to communicate with a kernel mode graphics driver 2829. In someembodiments, kernel mode graphics driver 2829 communicates with graphicsprocessor 2832 to dispatch commands and instructions.

IP Core Implementations

One or more aspects of at least one embodiment may be implemented byrepresentative code stored on a machine-readable medium which representsand/or defines logic within an integrated circuit such as a processor.For example, the machine-readable medium may include instructions whichrepresent various logic within the processor. When read by a machine,the instructions may cause the machine to fabricate the logic to performthe techniques described herein. Such representations, known as “IPcores,” are reusable units of logic for an integrated circuit that maybe stored on a tangible, machine-readable medium as a hardware modelthat describes the structure of the integrated circuit. The hardwaremodel may be supplied to various customers or manufacturing facilities,which load the hardware model on fabrication machines that manufacturethe integrated circuit. The integrated circuit may be fabricated suchthat the circuit performs operations described in association with anyof the embodiments described herein.

FIG. 29 is a block diagram illustrating an IP core development system2900 that may be used to manufacture an integrated circuit to performoperations according to an embodiment. The IP core development system2900 may be used to generate modular, re-usable designs that can beincorporated into a larger design or used to construct an entireintegrated circuit (e.g., an SOC integrated circuit). A design facility2930 can generate a software simulation 2910 of an IP core design in ahigh level programming language (e.g., C/C++). The software simulation2910 can be used to design, test, and verify the behavior of the IP coreusing a simulation model 2912. The simulation model 2912 may includefunctional, behavioral, and/or timing simulations. A register transferlevel (RTL) design 2915 can then be created or synthesized from thesimulation model 2912. The RTL design 2915 is an abstraction of thebehavior of the integrated circuit that models the flow of digitalsignals between hardware registers, including the associated logicperformed using the modeled digital signals. In addition to an RTLdesign 2915, lower-level designs at the logic level or transistor levelmay also be created, designed, or synthesized. Thus, the particulardetails of the initial design and simulation may vary.

The RTL design 2915 or equivalent may be further synthesized by thedesign facility into a hardware model 2920, which may be in a hardwaredescription language (HDL), or some other representation of physicaldesign data. The HDL may be further simulated or tested to verify the IPcore design. The IP core design can be stored for delivery to a 3^(rd)party fabrication facility 2965 using non-volatile memory 2940 (e.g.,hard disk, flash memory, or any non-volatile storage medium).Alternatively, the IP core design may be transmitted (e.g., via theInternet) over a wired connection 2950 or wireless connection 2960. Thefabrication facility 2965 may then fabricate an integrated circuit thatis based at least in part on the IP core design. The fabricatedintegrated circuit can be configured to perform operations in accordancewith at least one embodiment described herein.

Exemplary System on a Chip Integrated Circuit

FIGS. 30-32 illustrate exemplary integrated circuits and associatedgraphics processors that may be fabricated using one or more IP cores,according to various embodiments described herein. In addition to whatis illustrated, other logic and circuits may be included, includingadditional graphics processors/cores, peripheral interface controllers,or general purpose processor cores.

FIG. 30 is a block diagram illustrating an exemplary system on a chipintegrated circuit 3000 that may be fabricated using one or more IPcores, according to an embodiment. Exemplary integrated circuit 3000includes one or more application processor(s) 3005 (e.g., CPUs), atleast one graphics processor 3010, and may additionally include an imageprocessor 3015 and/or a video processor 3020, any of which may be amodular IP core from the same or multiple different design facilities.Integrated circuit 3000 includes peripheral or bus logic including a USBcontroller 3025, UART controller 3030, an SPI/SDIO controller 3035, andan I²S/I²C controller 3040. Additionally, the integrated circuit caninclude a display device 3045 coupled to one or more of ahigh-definition multimedia interface (HDMI) controller 3050 and a mobileindustry processor interface (MIPI) display interface 3055. Storage maybe provided by a flash memory subsystem 3060 including flash memory anda flash memory controller. Memory interface may be provided via a memorycontroller 3065 for access to SDRAM or SRAM memory devices. Someintegrated circuits additionally include an embedded security engine3070.

FIG. 31 is a block diagram illustrating an exemplary graphics processor3110 of a system on a chip integrated circuit that may be fabricatedusing one or more IP cores, according to an embodiment. Graphicsprocessor 3110 can be a variant of the graphics processor 3010 of FIG.30 . Graphics processor 3110 includes a vertex processor 3105 and one ormore fragment processor(s) 3115A-3115N (e.g., 3115A, 3115B, 3115C,3115D, through 3115N-1, and 3115N). Graphics processor 3110 can executedifferent shader programs via separate logic, such that the vertexprocessor 3105 is optimized to execute operations for vertex shaderprograms, while the one or more fragment processor(s) 3115A-3115Nexecute fragment (e.g., pixel) shading operations for fragment or pixelshader programs. The vertex processor 3105 performs the vertexprocessing stage of the 3D graphics pipeline and generates primitivesand vertex data. The fragment processor(s) 3115A-3115N use the primitiveand vertex data generated by the vertex processor 3105 to produce aframebuffer that is displayed on a display device. In one embodiment,the fragment processor(s) 3115A-3115N are optimized to execute fragmentshader programs as provided for in the OpenGL API, which may be used toperform similar operations as a pixel shader program as provided for inthe Direct 3D API.

Graphics processor 3110 additionally includes one or more memorymanagement units (MMUs) 3120A-3120B, cache(s) 3125A-3125B, and circuitinterconnect(s) 3130A-3130B. The one or more MMU(s) 3120A-3120B providefor virtual to physical address mapping for graphics processor 3110,including for the vertex processor 3105 and/or fragment processor(s)3115A-3115N, which may reference vertex or image/texture data stored inmemory, in addition to vertex or image/texture data stored in the one ormore cache(s) 3125A-3125B. In one embodiment, the one or more MMU(s)3120A-3120B may be synchronized with other MMUs within the system,including one or more MMUs associated with the one or more applicationprocessor(s) 3005, image processor 3015, and/or video processor 3020 ofFIG. 30 , such that each processor 3005-3020 can participate in a sharedor unified virtual memory system. The one or more circuitinterconnect(s) 3130A-3130B enable graphics processor 3110 to interfacewith other IP cores within the SoC, either via an internal bus of theSoC or via a direct connection, according to embodiments.

FIG. 32 is a block diagram illustrating an additional exemplary graphicsprocessor 3210 of a system on a chip integrated circuit that may befabricated using one or more IP cores, according to an embodiment.Graphics processor 3210 can be a variant of the graphics processor 3010of FIG. 30 . Graphics processor 3210 includes the one or more MMU(s)3120A-3120B, cache(s) 3125A-3125B, and circuit interconnect(s)3130A-3130B of FIG. 31 .

Graphics processor 3210 includes one or more shader core(s) 3215A-3215N(e.g., 3215A, 3215B, 3215C, 3215D, 3215E, 3215F, through 3215N-1, and3215N), which provides for a unified shader core architecture in which asingle core or type or core can execute all types of programmable shadercode, including shader program code to implement vertex shaders,fragment shaders, and/or compute shaders. The exact number of shadercores present can vary among embodiments and implementations.Additionally, graphics processor 3210 includes an inter-core taskmanager 3205, which acts as a thread dispatcher to dispatch executionthreads to one or more shader core(s) 3215A-3215N and a tiling unit 3218to accelerate tiling operations for tile-based rendering, in whichrendering operations for a scene are subdivided in image space, forexample to exploit local spatial coherence within a scene or to optimizeuse of internal caches.

Embodiments of the present invention include methods and systems forboosting deep neural networks for deep learning.

In one example, for a method, a deep neural network includes a firstshallow network and a second shallow network. A first training sample isprocessed by the first shallow network using equal weights. A loss forthe first shallow network is determined based on the processed trainingsample using equal weights. Weights for the second shallow network areadjusted based on the determined loss for the first shallow network Asecond training sample is processed by the second shallow network usingthe adjusted weights.

In one example, an AdaBoost boosting algorithm is used to determine theloss for the first shallow network.

In one example, the first and second shallow networks are combined.

In one example, a system for a server includes a processing core, an I/Ocontroller hub, and a graphics processor. The processing core has a deepneural network (DNN) with a plurality of shallow networks. The I/Ocontroller hub is coupled to the processing core and provides network,data storage, and DNN access to the processing core. The graphicsprocessor is coupled to the I/O controller hub. The graphics processorprocesses a subset of testing sample using the shallow networks of theDNN. The graphics processor also determines a loss for each shallownetwork based on the processed subset of the testing sample. Thegraphics processor also adjusts weights based on the determined loss foreach shallow network.

In one example, the graphics processor uses an AdaBoost boostingalgorithm to determine the loss for each shallow network.

In one example, the graphics processor combines the plurality of shallownetworks.

In one example, at least one machine-readable medium comprises aplurality of instructions, executed on a computing device, to facilitatethe computing device to perform one or more operations comprisingprocessing a first training sample by the first shallow network usingequal weights. A loss for the first shallow network is determined basedon the processed training sample using equal weights. Weights for thesecond shallow network are adjusted based on the determined loss for thefirst shallow network. A second training sample is processed by thesecond shallow network using the adjusted weights.

In one example, the computing device is to perform one or moreoperations comprising determining the loss of the first shallow networkusing an AdaBoost boosting algorithm.

In one example, the computing device is to perform one or moreoperations comprising combining the first and second shallow networks.

In one example, a deep neural network including a first weak network anda second weak network implements a method that comprises processing afirst subset of training samples by the first weak network usinginitialized weights. A classification error is determined for the firstweak network on the first subset of training samples. The second weaknetwork is boosted using the determined classification error of thefirst weak network with adjusted weights. A second subset of trainingsamples is processed by the second weak network using the adjustedweights.

In one example, the second weak network is boosted using an AdaBoostboosting algorithm.

In one example, the first and second weak networks are combined into alinear combination of classifiers.

In one example, a system for a server includes a processing core, an I/Ocontroller hub, and a graphics processor. The processing core has a deepneural network (DNN) with a plurality of weak networks. The I/Ocontroller hub is coupled to the processing core and provides network,data storage, and provides DNN access to the processing core. Thegraphics processor is coupled to the I/O controller hub and processessubsets of testing samples using the weak networks of the DNN. Thegraphics processor also determines a classification error for each weaknetwork based on processed subsets of the testing samples. The graphicsprocessor also adjusts weights for each weak network based on adetermined classification error.

In one example, the graphics processor uses an AdaBoost boostingalgorithm to determine the classification error for each weak network.

In one example, the graphics processor combines the plurality of weaknetworks as a linear combination of classifiers.

The foregoing description and drawings are to be regarded in anillustrative rather than a restrictive sense. Persons skilled in the artwill understand that various modifications and changes may be made tothe embodiments described herein without departing from the broaderspirit and scope of the invention as set forth in the appended claims.

What is claimed is:
 1. In a deep neural network including a firstshallow network and a second shallow network, a method comprising:processing a first training sample by the first shallow network usingequal weights; determining a loss for the first shallow network based onthe processed training sample using equal weights; adjusting weights forthe second shallow network based on the determined loss for the firstshallow network; and processing a second training sample by the secondshallow network using the adjusted weights.
 2. The method of claim 1,further comprising determining the loss for the first shallow networkusing an AdaBoost boosting algorithm.
 3. The method of claim 1, furthercomprising combining the first and second shallow networks.
 4. A deepneural network (DNN) system comprising: means for processing a firsttraining sample by a first shallow network using equal weights; meansfor determining a loss for the first shallow network based on theprocessed training sample using equal weights; means for adjustingweights for a second shallow network based on the determined loss forthe first shallow network; and means for processing a second trainingsample by the second shallow network using the adjusted weights.
 5. TheDNN system of claim 4, further comprising means for determining a lossfor the first shallow network using an AdaBoost boosting algorithm. 6.The DNN system of claim 4, further comprising means for combining thefirst and second shallow networks.
 7. At least one machine-readablemedium comprising a plurality of instructions, executed on a computingdevice, to facilitate the computing device to perform one or moreoperations comprising: processing a first training sample by a firstshallow network using equal weights; determining a loss for the firstshallow network based on the processed training sample using equalweights; adjusting weights for a second shallow network based on thedetermined loss for the first shallow network; and processing a secondtraining sample by the second shallow network using the adjustedweights.
 8. The machine-readable medium of claim 7, wherein thecomputing device is to perform one or more operations comprisingdetermining the loss of the first shallow network using an AdaBoostboosting algorithm.
 9. The machine-readable medium of claim 7, whereinthe computing device is to perform one or more operations comprisingcombining the first and second shallow networks.